Tuesday, November 17, 2009

Finder comparison - 6x6 versus Digital 1.5 crop format (DX) and 135 Film Cameras

Usually your equipment does not give you to get better images, but sometimes it can really help. One of the major advantages of medium format SLR or TLR photography is the larger finder compared to both, 136 format and DX format digital photography. First I would like to show you the resulting Velvia slide, which was shot with an 80mm lens at EV 10.5 = 1/4 s at f/19, focussed to about 10 meters which should yield almost optimum depth of field.

I should have shot more wide open (for example at f/8) and I should have focussed closer because the image is not very sharp in 100% view scanned at 4000dpi (because of f/19 and focus distance of 10m). Anyway, the following image shows a medium format 99% finder image of 55mm x 55mm at 200 dpi (not really shot from the finder but scaled down from a scanned Velvia slide) - if you do not own the latest, brightest and most expensive focusing screen - less colorful, less contrast - less sharp (image is simulated, I did not include the crosshairs):

But I do not consider this to be a problem. It is not too bad if it appears worse in the finder than it really is - it might even help you to get better pictures. And it looks a little better with a modern focusing screen. The same subject in a DSLR with a crop factor of 1.5 (16mm sensor size, 95% finder, AF sensors not included) will look about like this:

I took the original image and only scaled it but did not alter color, contrast, or sharpness because modern finder usually look bright and clear. Of course the aspect ratio would be 3:2 instead of 1:1 as shown here, but if you want to end up with an aspect ratio of 1:1 (a square), you would need to crop. It is really shocking how much smaller the DSLR image is! The finder image will be larger if you plan to crop it or if you use a 135 film camera or an FX sensor (24mm image height = 24mm sensor size in portrait format = 135 film in landscape format):
Another large advantage is you usually use both of your eyes for focusing and composing. The image thus appears three dimensional. Moreover, you see detracting elements much easier in the frame because they are larger. With 6x6 you also do not need to rotate the camera - you can chose between square, landscape or portrait format after the image has been made.
As zoom lenses are much less common with medium format photography, you need to move in order to compose which also helps to find the best perspective. With zoom lenses, one often becomes lazy and does not try different perspectives in order to find the best one. But of course you can also use prime lenses with digital cameras and 135 SLRs.

Sunday, October 18, 2009

Whitewall Photolab Review

If you want to make large prints, it really makes sense to use medium format film (or even view cameras). Well exposed and sharp 135 film or DSLR images do not look any different to medium format images when printed small. Sure, 20 MP full frame digital cameras and medium format digital backs will also be fine, but medium format film is a very inexpensive method to obtain the same—or even better—results.

For a high quality and impressive print, the image of course needs to be sharp and well exposed.

I chose Whitewall because I saw images printed by Whitewall in a Lumas fine arts gallery - and I was impressed. Whitewall is the photo-lab which does all the printing for Lumas—and certainly for many other galleries.

Their prints are usually mounted on a backing board (aluminum di-bond) and are often covered with acrylic glass. I chose acrylic glass mounting for three of five prints and went without acrylic glass for the remaining two. You can mount the images directly to you wall and do not need a frame. And for my favourite pictures I did not want any disturbing frame.

Whitewall offers printer profiles on their website, so you can see what you will get on your monitor before submitting the image (if your monitor is calibrated). They also consider included color profiles.

You can choose any size and aspect ratio you like.

In my first test, I uploaded a DSLR image and chose only a small print. I was mainly interested if the color was accurate. The color was almost perfect and matched my screen. Only the black parts were a bit too dark, but they were okay if the print was brightly lit.

Then I uploaded 4 square medium format scans and ordered different sizes
  • 50 cm x 50 cm with acryl (20 x 20 square inches) = € 86
  • 65 cm x 65 cm with acryl (25 x 25 square inches) = € 136
  • 80cm x 80 cm without acryl (32 x 32 square inches) = € 126
So you pay about € 3,20 to € 3,44 per 10 cm x 10 cm (becomes a bit cheaper for larger areas).

This is the 50 cm x 50 cm image:

Beach Chairs

The original 8500 x 8500 pixels translate to 435 dpi when printed at 50 cm x 50 cm. I could have printed it more than 1 m wide (3 feet) with 200 dpi!

I ordered those two hand-held shots 65 cm x 65 cm:


Hohes Ufer
And finally I ordered this one in 80 cm x 80 cm:

Beach Chair

Tone and color reproduction are perfect (almost exactly as shown on my screen). On the wall, they look like this:


The images above look a bit more saturated here than they really are. A 100 % view from the upper right corner gives you a better impression on how the aluminum di-bond and acrylic glass look like (I did not make another shot, I simply cropped a full image. The bad quality of 100 % vieved DSLR images becomes apparent here):

The dimensions are exactly as stated in the order but Whitewall does not print 100 % of your file. I found they print 99 % of the image. This means that 2.5 mm of each side are missing on my 50 cm wide print (= about 50 pixels). This is no problem since other labs print 95 %, which means that 1.25 cm are missing on each side.

Whitewall makes very high quality prints, has a good website, good service, and a careful packaging. They even offer a proof print of a part of the image so you can be sure what color and tone you will get before you order a huge and expensive print. They are not really cheap but the results are worth it.

Thursday, October 8, 2009

Slide versus Negative (Fujifilm Velvia 50 vs Fujifilm Pro 160S)

Beach Chair
For this comparison, I shot the same subject first with Fujifilm Pro 160S and then with Velvia 50. It was made on July 14th, 2009 at 10 pm using a 80mm lens. I shot a backlit and high-contrast scene because I was curious about the larger latidude and tonal range that low contrast negative film like Fuji 160S is said to offer.
I took an incident reading at the beach chair in camera direction. For negative film, I reduced the exposure by a little more than one stop because of the back lighting and larger exposure latitude. I shot the 160 ASA negative thus at f/16 and 1 second (EV 8). The 50 ASA slide was shot at f/16 and 8 seconds (EV 5) without compensation because I shot it a little later and the sun was already set. The shot with Velvia 50 is shown above. The result with negative film is shown below.
The subject contrast is too large for both, slide and negative film. The negative still captures the sea, the sun and the sky. In the slide, the beach chair and the beach itself are exposed correctly, but the sky and the sea are intentionally overexposed. The slide is completely white here. Looks like there is nothing beyond the beach which looks much more interesting to me than a dull sun, sea and sky visible in the negative film.

The following comparison shows a crop of the left side of each image, scaled to 50 percent. Upper part: negative, lower part: slide. Velvia looks much more vivid but not sharper. There is more shadow detail due to the over exposure but negative film does not have any better highlights.

The next example shows part of the beach, the sea and the beach chair (click to see original file). Some clipped highlights are visible at the top of the beach chair but again the color looks much more vivid. I also increased the contrast of the image from the negative film by adjusting the curves, but I was not able to obtain the same or even similar result as with Velvia. Therefore it cannot be contrast alone which makes the image appear brighter and more detailed.

Negative film is able to capture high contrast scenes and still shows detail in the shadows and highlight but this does not mean that the image looks any better. To me, slide film looks much better in this case. Sharpness is the same, both in 50% and 100% view. These and some more images are collected in this Flickr album.

Wednesday, September 30, 2009

Film Highlight Rendition

Sunset Velvia
For many people, color is more important than sharpness. Velvia might have a lower contrast range and exposure latitude than negative film and maybe even good digital cameras. But film's highlight capabilities are still unbeaten. Look at the sky, the clouds and the sun are naturally rendered. There is no color cast (hue) from bright to very bright areas and no blown-out highlights. If you click at the image above, you see the 4000dpi scan scaled down to 10%. It was shot with a 150mm f/4 lens focussed at 65 meters at f/16 and 1/4s (EV10) on Velvia 50 film. I pointed the light meter to the sky and added 2 stops, so the sky appears bright and the sea appears not too dark. This exposure was just right, I also made a shot at EV9 but it was slightly to bright.
I love the section underneath the sun where the sea looks like magma or lava:
Sunset crop shot with velvia
Digital cameras tend to clip highlights which results in strange color casts, usually making skin appear orange or yellow and this bright orange and yellow sky appear white and greenish. I have tried to simulate the digital image. The following image shows a 200% simulated digital image with a mouse over comparison to the 50% analog image.

The digital image is of course not as sharp but also has clipped highlights but is brighter in the shadows. The sun is completely white and has greenish surroundings. The image from the film appears to have lower contrast but looks much more natural.

Sunday, September 20, 2009

4000dpi Medium Format Scan vs. 2000dpi Scan

Today I would like to compare 4000dpi vs 2000dpi scans. Tree shots are perfectly suited for sharpness comparisons. The shot was made by my friend Philipp with a Zeiss 50mm lens on Fuji Velvia 50 probably at EV 14, which is f/11 at 1/125s. It was shot hand-held. Its a beautiful subject in beautiful light. And the slight underexposure and vignetting helps to keep the attraction centered to the main subject. In 100% view the image is sharp, but not extremely sharp. It is a typical medium format sharpness. The image above shows the original scan rotated by 0.4 degrees and scaled to 5 percent. It was rotated in order to keep the black frame lines straight.
I used the original, non-rotated file and an image downsampled to 2000dpi (also not rotated) for the first comparison. I compared the original version at 100% and the downsampled file at a 200 % view and it was impossible to see a difference. I also did not see any difference between the 400 percent and 200 percent view.
Then I brought rotating into play. I rotated the original file and I rotated the downsampled file by the same amount. Then I enlarged both versions to 200 and 400 percent respectively and was finally able to see a difference (mouse over for the 2000 dpi version):

It is mainly the film grain which makes the first image appear sharper. No real details are lost but anyway the 2000dpi looks less sharp. Please consider that this is not a 100 % view but a 200 % and 400 % view. It is hard to see anything at 100 % here. I recommend 2000dpi scans when file size is critical and the shot is not extremely sharp from the beginning. You will still get top-quality compared to an image from a digital camera or a scan from 135 film. You will still get a good quality after rotating or other transforming but the quality of a transformed 4000dpi scan is clearly better - at least when you plan to make huge prints of it.

Sunday, September 13, 2009

Hasselblad 80mm f/8 Sharpness Comparison with Fuji Pro 160S Film

Medium format photography is a reasonable compromise when you want a very good image quality and sharpness with relatively low weight and efford (compared to view cameras). Therefore it makes sense to look at the sharpness of both, lens and film. I chose a high contrast subject – a tree lit by evening light against a bright background. The incident light meter gave me a reading of EV15. It was very windy and no tripod was used. But a 1/500 s shutter speed should compensate for this. Anyway, we want to look at images from real conditions in the field and not at test charts shot in a lab.
I shot it with a Hasselblad Zeiss 80mm Planar lens at f/8 and 1/500 s shutter speed set to a distance of approximately 40 m (the tree). Hyperfocal distance as given on the lens is 18 m at f/8 but this value is calculated for a huge circle of confusion. Do not believe depth of field scales, they only give you the acceptable sharpness for small enlargements!). The film was a Fuji Pro 160S with an ASA speed of 160. It gives natural colors, has a relatively low contrast and is thus ideally suited for portraits. According to the manufacturer's MTF graph, it should be about as sharp as Fuji Velvia 50. It has a response of 70% at 50 cycles/mm whereas Velvia 50 has only about 45%.

It was scanned with a Nikon Super Coolscan 9000 ED at 4000 dpi and 8 bit per color. The print would be 1.1 m times 1.1 m (43 feet wide) if you print it at 200 dpi. You would need a 75 megapixel camera in order to snap at least a comparable black and white image (for color, you would need approximately 3 to 4 times as many pixels).
The image on the left shows the center sharpness at 100%. The lens should be at peak sharpness here (in the center and at f/8, it might be even sharper when focused to closer distances). This corresponds to a 38 mm x 38 mm square at 200 dpi (1.5 inches). Note how the extremely fine details of the smallest branches are still resolved. At such high spatial frequencies, contrast on film is very low due to both, lens and film performance. With dark braches in front of a bright sky, at least subject contrast is large. Otherwise, no details would probably been resolved at this level.
No unsharp mask or any sharpening algorithm was applied. I think this would only enhance film grain and remove the nice analog look, which means that film and lens behave just the way as described above. Sharpness does not vanish suddenly at a certain frequency as it does with digital. It is a nice, smooth transition between parts with high and low sharpness. The image on the right shows another example at 100%, this time a little off-center (17 mm distance to the center of the negative). The background sky (and sea) is less bright here, but small individual branches are still easily seen. Overall sharpness does not look extremely good, but this is because no unsharp mask has been applied. We are used at looking at digital images at 100% magnification with an unsharp mask applied almost always. This effect partially compensates for the sudden drop in sharpness at the digital image's Nyquist frequency. As on the image above, a little noise is also visible, which originates from the film itself. 160 ASA film at 4000 dpi does not look as clean as images from a digital SLR at 100 or 200 ASA.
The last example is from the very top of the image (22 mm off the center), showing branches nicely lit by the evening low, orange evening sun. You almost see the transition between bright and dark on each individual branch.
Image sharpness of a scanned medium format film is much larger than anything from amateur digital cameras. But of course this sharpness is only visible in huge prints. But much more important than sharpness is color and the highlight capability. Look at the clouds -they are very bright but there are no washed-out highlights in this scan. I will look at the highlight capability in one of my next posts.

Monday, September 7, 2009


Welcome to my blog. In the following posts, I would like to share my experience with converting from digital photography to analog medium format (6x6, 120 film). I will try to answer questions like
  • why should you upgrade to 120 film?
  • what are the drawbacks?
  • what do you gain?
But mainly I will share results from scanning medium format photographs and I would like to encourage you to share your thoughts, too.
Ahrenshoop Velvia 50 EV9 IMG004I chose velvia-film.blogspot.com as a URL because this is easy to remember. I will not only cover Velvia film, but Velvia is of course very popular - for me and many other photographers.

The image above shows a 6x6 photo shot with Velvia 50 film. I shot it a couple of months ago at an EV of approx. 9 at f/16 and 1/2 s. I read the sky with a light meter and added two stops (which was a bit too much). Unfortunately, Flickr does not show its original resolution of 8525x8525 pixels. Thus, I show a 100% crop here (click to enlarge):

Not really impressive, is it? But this is film at f/16 and 4000 dpi. Moreover, the subject is backlit. But the highlights look good, altough the overall image is slightly overexposed. Please do not forget that this is only 0.71% of the original image area! For comparison, I rescaled the image to one third in order to simular a typical resolution of a 12 MP DSLR and sharpened it very slightly. The sensor of the simulated digital camera has about 4260 x 2840 pixels. Of those, only 2840 x 2840 pixels are usable with a square!). This in not really fair because a Bayer interpolating DSLR can resolve brightness with 12 million pixels but every pixel can see only either red, green, or blue. It needs four pixels to see the original color! A better way would be to rescale only luminance to 12 MP, but color to 3 or 4 MP. But anyway, we ignore that for now and give digital a little unfair advantage. What does it look like?
Well, this is difficult to compare ... It's much smaller ;-) Let's compare the cropped image with the crop of the blown
up image from a simulated digital camera. The digital image (mouse over) looks sharpened, more grainy and has much less detail and fewer real colors.

Conclusion: This is a very brief comparison but the difference is obvious.