Sleeklens Photoshop actions – a review

Sleeklens Photoshop actions – a review

by Jonathan Bourla (


Hi.  A little while ago I was approached by the Danish firm Sleeklens to review a set of Photoshop actions that they make for Landscape photographers.  They also produce their equivalent for Lightroom users.

Now, I have an established way of “post-processing” my photos on Photoshop, basically mirroring what I used to do in the darkroom – contrast control; dodging & burning; and unsharp masking.  My process on Photoshop takes a long time, slowly building up the effect I want.  Sleeklens’ workflows aim to simplify and shorten such post-processing for photographers.

But I ignored the first approach from Sleeklens, thinking that I am content with how I do things.  When their second approach came, I had a change of heart and thought it would be interesting to try them out.

Those of you who know me know that I produce black and white photographs.  Sleeklens’  Landscape Adventure Collection of Photoshop actions is intended for colour photographs.  I learned later that there is a Sleeklens collection for black and white, which would have been more appropriate for me, but digging out some colour images I proceeded to experiment with the Sleeklens’ actions (once I’d loaded them onto my Photoshop, Creative Cloud).

The actions are grouped into eight categories.  Seven of these relate to image manipulations, being called “Exposure”, “Base”, “Tone”, “All-in-One”, “Enhance”, “Specialty”, and “Temperature”.  The last category, called “Web File Preparation”, gives actions to resize images.

In the documentation with the actions, Sleeklens has example shots in which a series of actions have been applied to get to their desired outcome.

Some actions have self-explanatory names, like “Warm Highlights”.  Others are more vague, such as “Clarity” and “A Good Place to Start for Landscapes”.  It takes a bit of experimentation to find the actions that suit your particular image, and it seems unlikely you will want to use the same combination of actions for all your images.  So familiarity and experimentation with the various actions is needed before you can know which ones to apply.

One thing to note is that Sleeklens recommends you to flatten your file before applying an action and importantly to keep saving the file if you’ve applied an action whose result you are happy with.  I did try to use History in Photoshop to return to before the current action, but there were so many processes listed in History that it wasn’t easy to find where this current action began.  So keep flattening and saving when you are pleased.  If you apply an action which doesn’t give a result you like, return to the version of the image you saved from before.

There are over sixty actions in the collection I received, offering a variety of different effects.  You can find out more from Sleeklens about their Photoshop actions at the two following links:

And Sleeklens also offers an editing service, details of which can be found at:

That’s it for now.  Thanks for reading.


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Choosing a digital camera – megapixels, sensor size, pixel pitch?

Choosing a digital camera – megapixels, sensor size, pixel pitch?

by Jonathan Bourla (

The choice of modern digital cameras seems bewildering. What separates one from another? It would seem that most laypeople judge a digital camera’s capabilities solely by the number of megapixels of its sensor. This is great for the manufacturers, persuading customers to part with their present camera with one for more megapixels. But is it the whole story?

In film cameras, in general the larger the film size the better, in terms of image quality. At the small end was the very popular 35mm format. There were smaller formats than this, but they weren’t great and didn’t take away from 35mm’s prominence. The next step up, the choice of many professionals, was medium format. The next step from this was large format. As with a lot in photography, the choice was one of compromise. Medium format was, for many professionals, a great compromise between good image quality and ease of use and portability.

Now, in the digital world, 35mm sensors have become the pinacle. You can get medium format digital cameras and backs, but they are extremely expensive and out of reach of all but a small number of professional photographers. So for most, 35mm, also known as Full Frame, is the best and what serious photographers aspire to owning. There are a number of different sensor physical sizes, ranging downward from Full Frame to relatively tiny sensors used in the cameras in some smart phones. In the chart here are some common sizes. Note that the names of these sensors are often rather weird. For example a one inch sensor is not one inch in either dimension, or the diagonal measurement. Another thing is the APS-C sensor size – Canon’s version of this sensor is of a slightly smaller size than the APS-C sensors used by other manufacturers.


So, which is it, what should we be concerned with – the number of megapixels or the physical size of the sensor? As it turns out, it’s a combination of both. What is important in several ways is the physical size of each pixel. The bigger the pixel size, the better. This measurement is often called the Pixel Pitch, and is measured in microns ( a millionth of a meter). Let’s have a look at the Pixel Pitch measurements for a range of cameras. Remember, higher is better….

But first, I want to point out that you will notice in the tables below links to .  If you click on a particular link, you will be taken to the page on associated with more details on that particular camera.  If you do click on one of these links and subsequently make a purchase on, I receive a small commission.  I (Jonathan Bourla) am a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to .

Ok, let’s have a look at the cameras and their numbers:

Camera (Smart Phones)Pixel Pitch in micronsnumber of megapixelssensor typeLinks to  
Apple iPhone 6
Samsung Galaxy S61.1161/2.6"
Samsung Galaxy S6
Camera (Compact cameras)Pixel Pitch in micronsNumber of megapixelsSensor TypeLinks to 
Panasonic LX1003.912.8Micro 4/3
Panasonic LUMIX LX100
Fuji X302.1122/3"
Fujifilm X30
Sony RX102.420.21 inch
Sony DSCRX10/B
Panasonic FZ10002.420.11 inch
Panasonic Lumix DMC-FZ1000
Canon SX60HS1.316.11/2.3"
Canon PowerShot SX60 HS
Panasonic TZ70/ZS501.412.11/2.3"
Panasonic LUMIX DMC-ZS50K
Olympus Tough TG-31.3161/2.3"
Olympus TG-3 Waterproof
Canon Powershot D301.412.11/2.3"
Canon PowerShot D30 Waterproof
Sony W8001.120.11/2.3"
Sony W800
Camera (Entry-level SLR)Pixel Pitch in micronsNumber of megapixelsSensor typeLinks to 
Nikon D33003.924.2APS-C
Nikon D3300
Nikon D32003.924.2APS-C
Nikon D3200
Canon EOS 750D3.724.2APS-C
Canon EOS 750D
Nikon D55003.924.2APS-C
Nikon D5500
Nikon D53003.924.2APS-C
Nikon D5300
Canon EOS 700D (Rebel T5i)4.318APS-C
Canon EOS Rebel T5i
Canon EOS1200D (Rebel T5)4.318APS-C
Canon EOS Rebel T5
Pentax K-504.816.3APS-C
Pentax K-50
Sony Alpha a584.320.1APS-C
Sony SLT-A58
Pentax K-S14.320.1APS-C
Pentax K-S1
mid-level SLR
Pixel Pitch in micronsNumber of megapixelsSensor typeLinks to 
Nikon D71003.924.1APS-C
Nikon D7100
Canon EOS 7D Mk24.120.2APS-C
Canon EOS 7D Mark II
Nikon D72003.924.2APS-C
Nikon D7200 DX
Pentax K-S24.320.1APS-C
Pentax K-S2
Canon EOS 760 D (Rebel T6s)3.724.2APS-C
Canon EOS Rebel T6s
Canon EOS 70D4.120.2APS-C
Canon EOS 70D
Sony a77 Mk23.924.3APS-C
Sony A77II
Pentax K-3 ii3.924.3APS-C
Pentax K-3II
Camera - High End SLRPixel Pitch in micronsNumber of megapixelssensor typeLinks to 
Canon EOS 5DS4.150.6Full Frame
Canon EOS 5DS
Nikon D8104.936.3Full Frame
Nikon D810 FX
Canon EOS 6D6.520.2Full Frame
Canon EOS 6D
Nikon D7506.024.3Full Frame
Nikon D750
Canon EOS 5D iii6.222.3Full Frame
Canon EOS 5D Mark III with 24-105mm lens
Nikon D4S7.316.2Full Frame
Nikon D4S
Canon EOS 1DX6.918.1Full Frame
Canon EOS-1D X
Nikon Df7.316.2Full Frame
Nikon Df
Sony Alpha a996.024.3Full Frame
Sony Alpha a99
Camera - MirrorlessPixel Pitch in micronsNumber of megapixelssensor typeLinks to 
Sony A77ii6.024.3Full Frame
Sony Alpha a7II
Leica Monochrom6.918Full Frame
Leica M Monochrom
Leica Monochrom Type 2466.024Full Frame
Leica M Monochrom Typ 246
Leica M96.918Full Frame
Leica M9
Sony A7rii4.542.4Full Frame
Sony a7R II
Camera - Medium FormatPixel Pitch in micronsNumber of megapixelssensor typeLinks to 
Pentax 645Z5.051.4Medium Format 43.8x32.8 mm
Pentax 645Z
Leica S6.037.5Medium Format 45x30 mm
Leica S

The tendency for manufacturers is to squeeze more pixels on a given sensor size. But it was interesting to find that both Nikon’s and Canon’s flagship models had relatively low number of megapixels, as did the very high quality Leica models. It was interesting to see that the latest version of Leica’s Monochrom camera, the Type 246, had more megapixels than its predecessor, and consequently a lower pixel pitch rating. Perhaps people who have experience of both could comment on how they compare?

The highest rating cameras were Nikon’s D4S and Df with pixel pitch of 7.3, closely follwed by Canon’s EOS 1DX and Leica’s cameras such as the M9 and the previous generation Monochrom at 6.9 .

I had expected the Medium Format cameras/backs to be better than any smaller format models, but the medium format models I assessed had pixel pitch rating of 5.0 or 6.0 microns, less than the 6.9 or 7.3 of the models above. For larger prints, theory would suggest these medium format models to reign supreme. But does that still hold true when printing at smaller sizes? If pixel pitch were the overwhelming factor for image quality, it would seem rather close.

So there you go, a factor to consider when you next buy a digital camera – Pixel Pitch.

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Limited Editions

“Limited Editions” by Jonathan Bourla (

'Eroded-girder'-by-Jonathan-BourlaHello again! I want to talk a little about Limited Editions today.

Early on in my fine art photography journey, I wanted to address the issue of limited editions for my work. I knew that some of the photographers whose work I was inspired by had editions of one hundred. Locally I had also seen editions of just two or three.

The concept of limited editions came from printing techniques such as screen printing, where the materials used in the printing would degrade after each use, and so only a certain number of prints was possible before quality suffered.

Having limited editions for photography is a way of saying that the photograph isn’t mass produced. But I see photographers with editions of three hundred and fifty, or even five hundred. This clearly really is mass production, and to my mind calling them limited editions is just plain stupid.

In fact, when I discovered that my favourite photographers had editions of one hundred I had the same feeling. But at the other extreme the editions of just two or three are really limiting for a reproducible artform. Photographers’ printing styles change over time – often one can tell a print of a subject from late in the photographer’s career from one produced earlier on. This is true of traditional processes such as silver gelatin photographs, where what I call the Interpretation stage takes places as part of the printing process. With today’s Pigment Ink prints, known widely as Archival Pigment prints, although the Interpretation has taken place before the actual printing process, it is still quite likely over time that the photographer will want to adjust the look of the photograph as his/her techniques and skills mature, and materials change.

The opposite of a Limited Edition is called an Open Edition, where there is no limit to the number of photographs produced. An Open edition has no maximum. Despite no stated maximum, some photographers number each photograph produced. I was quite surprised to discover that one of the great Ansel Adams’ photographs, in an Open Edition, resulted in over a thousand prints – making it far from the exclusive photograph I had thought it was.

I settled on an edition size of twenty five for my limited edition photographs.

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How to buy fine art photography, Part 1

How To Buy Fine Art Photography

By Jonathan Bourla (


Part 1

I want to look at fine art photography from the other side, the side of someone looking at purchasing a fine art photograph. I will cover matters of technique, limited edition numbers, pricing (and whether a photograph can be found for a lower price in one retail outlet than another), purchase guarantees, print longevity, and other issues.

Years ago when I attended a workshop in Ann Arbor, America run by the excellent photographer Howard Bond, I and the other participants were treated to viewing of works by a number of diverse Master photographers. They were quite different but they all had some technical characteristics in common. The first is they had excellent shadow detail, and the second they had an attractive tonal scale, otherwise known as Tonality. When these two attributes are lacking, it is often down to poor technique. Lets have a look at them in turn:




Above is a small jpeg of my photograph “Under Cornwallis Wharf”. You can see detail everywhere, including in the dark roof of the structure.

Below this is a cropped view of the underside of the structure. The picture beneath this is a simulation of what this shot with poor shadow detail would look like. In general, unless the photographer is aiming for a complete silhouette of the subject against a completely black background, it is desirable to be able to see detail in the dark areas of the photograph. However, in general we have become accustomed to black and white photographs with poorly rendered shadow areas, as one must be technically proficient to do this well, and sadly this often isn’t the case.

The second issue is of a photograph’s tonality. Or in computer terms, the greyscale. Poor quality black and white photographs are often just that: black, and white. With little in the way of a scale of grey tones. This often goes hand in hand with the shadow detail issue I raised a moment ago, and is also related to technique.

So these are two things to look out for when buying a fine art photograph. Can you see detail in the shadow areas where you think there should be some? And is there a nice range of tones in the photograph, not just a semi-featureless dark area and a washed-out light area?

I hope this has been of some help. Next time I will look at limited editions. Bye for now.

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An insight into film scanning and manufacturers’ claimed resolutions

An insight into film scanning and manufacturers’ claimed resolutions

by Jonathan Bourla (


For some time when reading photo forums on scanning, I have realised how ignorant many people are about the scanner manufacturers’ claimed resolutions for their products. One time when offering up a response to a question regarding scanning, the subsequent answer to mine suggested I “upgrade” my admittedly long in tooth and out of production scanner with a new one with significantly higher resolution capability. What this person didn’t grasp is what I am going to address below.

My first film scanner was a Microtek i900. This scanner could scan film formats from 35mm through medium format up to 4×5 inch. The scanner was to be used to digitize my 4×5 inch black and white negs, plus the occasional 6×7 cm negs from my Mamiya 7 camera.

The box for my i900 scanner touted resolution of 6400×3200 pixels per inch. What I found out subsequently was that the scanner had two scanning arrays, separated by half a pixel. Each of these was 1600 pixels per inch, and to get higher resolution than that the second array came into play, providing in theory a maximum resolution of 3200 pixels per inch. Note the “in theory”. I did a test scan at 3200 pixels/inch, and found the result no better than a scan at 1600 pixels/inch followed by interpolation in Photoshop. In other words, you got a lot more pixels, but the actual resolution was no better than the lower scan. I have seen a review of a different scanner by photo-I-uk which found exactly the same effect. Their reviewed scanner was an Epson with an advertised resolution of 4800 pixels/inch, and they found the optimum resolution was actually 2400 pixels/inch. So I quickly came to realise I should scan everything at 1600 pixels/inch.

This shouldn’t have been a surprise to me anyway if one looked at Microtek’s scanner lineup, the scanner just up from mine was the 1800f, which as the model name suggests, this time accurately, promises a maximum resolution of 1800 pixels/inch. The difference between this model and my own was the more expensive one used a single scanning array.

Fast forward a while, and I had the opportunity to buy a demonstration use only Microtek 2500 from the Microtek dealer/importer. This was quite an old model, using the SCSI interface (which discovered what preceded the current USB that we all know). I needed to use an early series Mac computer. The computer died once, with the power supply failing. Finding it was impossible to locate a replacement, I decided to use a standard computer power supply (and a second power supply needed to power the Apple screen) and with them sitting ontop of the computer box, with the numerous wires diappearing into the box through a less than perfect hole in its top. Now when I think about itI can’t believe I did this modification to the computer, and for some reason would have been probably too scared to do that today if the need arose.

The scanner produces marvellous scans. I read a review of my scanner on View Camera magazine which confirmed it produces a resolution close to it’s specified 2500. Recently, with my belongings (including scanner) in storage while my wife, my elderly dog, and I have been on an adventure travelling around the New Zealand’s South Island, partly on a photographic project. I got some films scanned by an Australian firm using an Imacon scanner. The scans do indeed seem very good, but I would rate them as similar to scans I’ve got from my Microtek 2500.

If you think I have a wonderful scanning experience with my 2500 scanner, you’d be wrong. I am afflicted by the computer and/or scanner freezing, more often than I would like – obviously I don’t want it to happen at all! I am using scanning software called Vuescan, which is marvellous in that it supports a huge number of scanner models. I don’t know if I were to get the latest version of Vuescan whether it would be better, or just the same. Silverfast is a competitor. A version of it came as standard with my old i900, but unfortunately this wasn’t the case with my 2500. I’ve looked into getting Silverfast for my scanner, but it seems very expensive, and not knowing if it will be an improvement, I am reluctant to try it. I did notice they may offer trial versions, so I will have to go back to their site to investigate.

When I looked into getting the Imacon scans carried out while I didn’t have access to my own scanner, I also considered drum scans. There were several places that I contacted. They were all phenominally expensive. Also, they were all 8 bit scans, whereas I wanted 16 bit scans. If you are looking to do significant work in Photoshop or alternative photo editing program, then I consider it important to have the original scans done in sixteen bits. So this ruled out the drum scans. In the end I was very happy with the Imacon scans.

So to sum up, be very wary of the scanner resolutions promised by the manufacturers. A scanner offering 4800 or higher pixels/inch may actually really be one of 2400 pixels/inch. There’s nothing wrong with such a figure, but it’s nice to know what you’re getting, and comparing like with like.

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Yearning for a new camera – a modern condition


by Jonathan Bourla (


I’m sure it’s very common amongst photographers to hanker after a new, better camera. Is this yearning for something better the same now as it was when the photographic world was dominated by film cameras? Or is it different today?

I was thinking today about a typical professional film photographer who used a Hasselblad medium format camera. The decision making that may have gone into his decision to use and invest in a Hasselblad system may have been seeking better quality than 35mm could offer, yet offering more convenience and flexibility than a large format camera could offer, – large format users will attest to the slow, methodical operation and dedication needed. Would he hanker after an improved camera to satisfy his photographic needs? I doubt it

What about today’s digital world? This photographer would probably be using a medium format digital single lens reflex, like the rebadged Mamiya Phase Ones, with a medium format digital back. These backs are regularly superceded by similar models with incremental improvents in megapixel rating. I read of photographers who go through a sucession of upgrading of their medium format digital backs. Have you seen the prices of these backs? It must cost these photographers a fortune, and will there come a time when they say “enough is enough”? Professional cameras – well, all digital cameras –have much in common with technology purchases, such as computers. Every year or two we are faced by new models with increases in processing power, and through marketing we are encouraged to discard our “ageing” computer in favour of the very much better one on offer. I wonder if this equipment we are buying, including cameras, are made to a much inferior standard to what we used to enjoy, as the manufacturers know in a year or two we are more than likely to want to upgrade anyway.

Having written the above, which must seem quite negative, I have my eyes and heart set on a new camera to join my Mamiya 7 medium format arsenal. Although I am sorely tempted by a digital solution, the costs are great. I would love to have “front rise” movement of my big Gandolfi camera in the smaller Mamiya 7 size. I have come across a camera made by the firm of Plaubel called the Proshift. It’s an unusual looking camera, down to the shape of the integrated film back, which is very similar to Mamiya backs from their old 6×9 press cameras. The Proshift also has the 6x9cm format, with a fixed Schneider 47mm Super Angulon lens, which has the same field of view as, if I recall correctly, a 17mm on a full frame 35mm camera. The Plauble has a clever viewfinder, which tilts up and down to mimic the effect of the rise dialed in. Originally these cameras came with a centre filter, which is quite important, but sadly lacking from many being sold online. I will keep my eyes open.

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“Real” sized medium format sensors

“Real” medium format sized sensors

by Jonathan Bourla (




I’m interested in the fact that all medium format digital backs are six by four and a half centimetres or smaller in dimension. As a photographer who uses a large format camera for much of my work, medium format seems small. I have a six by seven centimetre camera – a Mamiya 7 – which is excellent, but I never considered a six by four and a half centimetre camera, thinking it too small and too similar in format size to 35mm. I have read that early medium format digital backs were more 35mm than medium format in size. Why are there no six by seven centimetre sized digital sensors? I have read about production difficulties with digital sensors, with a high failure rate. Maybe this is true, I just don’t know, but would love to find out. But it sure would seem better to have digital sensors the size of what I consider “real” medium format.

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Medium format digital vs the best of 35mm digital continued

by Jonathan Bourla (

rock_faceI have become a bit obsessed thinking about these two digital camera systems. My wife pointed out to me that this started as a bit of a pipe dream but has become something real, thinking about actually making a purchase. But I think I have been kidding myself if I’ve been thinking I could afford the medium format based system. The prices for current medium format digital backs are simply astronomical, and beyond the means of most photographers. I have seen photographers justifying their purchase of a medium format digital back in terms of the processing and scanning costs they have had previously for their film negatives and slides. They seem to have taken a huge number of film exposures every year. And maybe in those circumstances one can equate the cost of the medium format digital back to the costs associated with digitizing their film negatives or slides. But I produce a relatively small number of negatives per year, with the vast majority being “keepers”. So this justification of a medium format digital back’s cost just doesn’t apply to me. Second hand medium format digital backs are far more affordable than their new counterparts, but still quite costly. I worked out the cost of a used Phase One P45+ back with Cambo WRS technical camera and two Schneider lenses as about thirty thousand New Zealand dollars, probably more. Although I’ve been thinking and talking about this system as a possibility, I can see on reflection that I couldn’t justify spending so much money on a camera system to replace my 4×5 inch Gandolfi/Schneider system, just for the sake of the convenience of not developing and then scanning my film negatives.

I have read of rumours that Sony will be producing its own medium format digital camera, at some stage in the near future. This isn’t surprising, as I understand that Sony produces the sensors used in some of the medium format digial backs by Phase One and possibly others. Sony has produced a very well regarded full frame 35mm camera, the A7r, which I will mention again in a moment, and it is at a price level which makes other competing seem rather dear. So there is hope Sony could make a medium format camera system that would be far more affordable than the Phase Ones and the like. I have read online of justifications why the current medium format backs are so expensive. The main one being that the market for them is so small so the price has to be high (read very very high). Well, I’m no high powered businessman, but that was surely their choice – they could have made the price more affordable, and surely there would have been thousands more photographers able to buy their products. I have read that it is hard to make these larger sensors, with a large percentage discarded due to faults. I have no idea if this is true or not, but I find it hard to believe the discard rate is so high to justify the high prices. But I do have high hopes in Sony producing a camera system which will be accessible to a far larger proportion of photographers seeking a high quality alternative to the likes of my 4×5 inch camera. Whether it would have tilt/shift capabilities I wonder, and somehow doubt, but one can but hope.

The other system I was thinking about is the Sony A7r (I just mentioned) in conjunction with Canon tilt/shift lenses by means of an adapter made by a firm called Metabones. I had seen some impressive looking photos taken with this system, and I was very interested. But I’d seen these photos on my cell phone. Today I saw the same photos online on my laptop, and they didn’t seem to have the sharpness and quality I had thought when I first saw the cell phone versions. I have read quite a few reviews of the A7r, which all said how good it was, but the accompanying photos didn’t seem very sharp or detailed. This had me worried. Clearly I will need to verify this for myself by renting one of these cameras at some stage. I see the A7r/Canon system to be a replacement for my Mamiya 7, not for the larger Gandolfi setup. I would really appreciate the tilt and shift capabilities, which the Mamiya 7 lacks. The reviewers of the A7r cameras all seemed to be 35mm camera users, and as such, with all due respect, may not have the quality expectations of a medium or large format film user. But the A7r/Canon system is certainly far more affordable than a medium format competitor, and I could partly offset the cost by selling my Mamiya 7 outfit. I’m in the middle of things at the moment so it may be a while before I go and rent an A7r, but I look forward to when I do to quell the questions floating around my mind as to its image quality.

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Medium format digital vs the best of 35mm digital

by Jonathan Bourla (

The term “medium format” covers a range of photographic sizes. Some years ago when I was looking to buy a medium format film camera, I thought of 6x6cm and 6x7cm as the main sizes, totally disregarding the smaller 6×4.5cm as, well, too small, too close to 35mm to be thought of as a different format. Well today in this digitally dominated world, medium format is 6×4.5cm alone. One pays such a huge premium for medium format digital equipment over their 35mm competition that it would seem to rule it out for the majority of former-film photographers, except for apparently highly paid commercial photographers. There is no large format digital apart from scanning backs which require the camera back to be tethered to a computer, which limits their use in the field.

Being a devout film photographer, I am surprised to be toying with the idea of aquiring a digital back and camera system. It would have to offer similar sharpness and tonality to my main camera, a 4×5 inch view camera. I have questions: how much better is a medium format digital than full-frame 35mm cameras? And is the medium format going to compare favourably with my view camera?

Recently I saw some fantastic photos online that had been taken with a Sony A7R 35mm camera with Canon tilt/shift lenses by means of an adapter. They got me thinking that maybe such a full frame 35mm system might be good enough. But of course, small jpegs online don’t really give an indication of how good medium and large sized prints would be. I have found a rental place that has these cameras (but not the tilt/shift lenses) so maybe I will see about renting one. This camera has 36 megapixels. With a similar number of megapixels is the P45+ back, made by Phase One, and available on the used market at greatly lower price than its current generation replacements. How much better is this back compared with the 35mm system? A year or two ago I read about a well-known, very talented colour landscape photographer who went from a 4×5 inch camera to a digital system using a P45+ back. He said the results from the digital system were similar in quality to the drum scans he obtained from his large format camera.

But I really don’t understand the megapixel numbers for digital cameras and systems. For my own negatives, I scan at my (very good) scanner’s maximun resolution of 2500ppi, and obtain scan with the equivalent of one hundred and twenty five megapixels. The photographer I mentioned, who scanned using a drum scanner, would no doubt have scanned at a higher resolution and so would have files in excess of my one hundred and twenty five megapixels. So how can a digital back producing just thirty nine megapixels really produce similar results to a one hundred and twenty five megapixel scan? I don’t understand it.

There is another camera rental place that rents out medium format digital equipment. Not Phase One but Leaf, but again I may have to rent the equipment to get an idea if it really compares with my large film camera. In proportion to the difference between medium format and 35mm cameras when new, the rental price for the medium format back and camera is very expensive. Not knowing anyone with such equipment, I may be forced to spend the money. Sometime. I shall carry on thinking in the meantime…

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Tutorial – Diffraction, that little known factor in image sharpness

Tutorial – Diffraction, that little known factor in image sharpness

by Jonathan Bourla (

When I was a teenager, shooting 35mm colour slides, I didn’t take diffraction into consideration. In my later school years I had heard of diffraction in my Physics class, but for some reason didn’t think how this applied to my photography. It was only in my early thirties, using a large format camera, that I learned again of diffraction, and that I should certainly take it into account when seeking to achieve as sharp photographs as possible. This was at a workshop I attended run by the brilliant American photographer Howard Bond.

Lenses don’t perform equally well at all apertures. At large apertures, lenses are typically affected by aberrations, which degrade the optical performance. There are different types of aberrations, but in general their effect is reduced as the lens’ aperture is stopped down. At the other end of the aperture scale, at small apertures, the lens’ performance is adversely affected by diffraction.

So, the consequence of this is that somewhere in the middle of the aperture range the lens will perform at its best. Typically this is at f8 or f11, and this explains why the lens manufacturers quote their lenses’ performance at these apertures. Photography is a balancing act, with aperture, shutter speed, depth of field, etc all needing to be assessed, and coming to what the photographer considers the best compromise. Now I’m saying to be mindful of the optimum aperture as well.

For large format cameras, like the one I use, the lenses typically have maximum apertures of f5.6 or f8. So the optimum aperture is close to the maximum. However, the demands of achieving focus throughout the image, which tends to be a convention amongst large format photographers, often results in using smaller apertures than the ideal. This is sometimes called being diffraction limited.

Now for a small format camera lens, such as 35mm (film or digital), this optimum is some way from the lens’ maximum aperture, and along with achieving the necessary depth of field should be considered when selecting the aperture.

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