MicrobeHunter.com Microscopy Forum

Since some of the folks here like film photomicrography, and/or are familiar with it, here is a question, hopefully not too dumb or too philosophical.
In general, film cameras can produce very sharp images, I think about the same quality as 20MP digital cameras or better (under static, well illuminated conditions).
Dedicated 35mm microscope film cameras of the past, say from Zeiss or Olympus, were quality cameras, so, I believe, produced sharp images.
Those cameras had mechanical shutters (leaf or focal plane), internal mirrors, and nothing to "smooth" shutter release except for the cable release.
Moreover, those cameras were rigidly fitted onto the microscope, not "floating" above the eyepiece and supported by a separate frame.

So, how comes that nowadays, there is such concern about shutter- and mirror-induced vibrations ? is it because we Moderns try to visually zoom in, enlarge the image (by means of software or our eyes), and demand much more sharpness than microscopists in the past ?

I think we're spoiled! We expect to fasten our fancy new DSLR up to the scope and get instant gratification, just like taking an image of a field of flowers.

Plus,
1) the old in-the-lens leaf shutters had very little vibration, compared to modern SLRs with mirror-slap and focal-plane shutters;

2) not all cameras were rigidly connected to the scopes; mechanical systems made up of coupled or uncoupled components of different masses tied together or supported separately are very complicated, and trial-and-error is king when debugging sources of sway, and vibration effects; a lot of work in some cases to solve and fix.

3) Often tricks were used, such as open the shutter, THEN turning on the light source, exposing, turning off (or blocking) the light source, close the shutter;

4) cable releases were the preferred tool to prevent the massive movement caused by pushing on the shutter button; a shutter speed above say 1/200 sec is needed to prevent this, if not using a self-timer or remote release;

From what I've read, a 35mm film frame of ISO 100 film is more like 40MB digital; and a 4"x5" film can hold a 500MB image. The remaining film users are to be congratulated for their hard work.

Hi together,
here a couple to my thoughts on this topic:
- Our quality demands today are often ahead of our real needs: For a sharp picture only so much resolution is needed. From bigger images you step back further. Only if detail is really important you put your nose on the big print. Then think about 1024 x 768 forum resolution
- Film was slow. When exposing longer the shutter shock is only disturbing part time.
- Leaf shutters emit a rotary shock that probably is more compatible with microscope stands
- Many SLRs had mirror pre-release, so it was just the shutter shock
- Micro photography was a job few people liked: Much work and always the risk of ending with bad results
- The Phomi 1 used long exposure times, you added ND filters if necessary.
- The Phomis sold stupidly well, 55000 over 30 years at a really high price. Reason was the image quality (further improved from model to model) and dependability once set up correctly for the film in use.
- My own measurements (good SLR, 200 ISO colour negative film) showded a resolution of 12 MP real detail, probably roughly equal to a 20 MP bayer sensor.
- demands must have generally been lower. Image editing was restricted to dark room technique and stacking was not available.
- On the other hand side they produced stunning micro photographs: http://www.baertierchen.de/feb2004.html
- Micro photograph at this level was not the work of amateurs done between 12 and lunch.

Bob

When I bought my Leitz MIKAS adapter a few years ago it came with a Nikon M35 camera attached. That camera has no shutter, it has a dark slide that you pull out by hand and what looks like a shutter button. The shutter button is just for releasing the film advance to go to the next frame. I think shutter shake has always been a concern.

If I use a camera with a focal plane shutter the first thing I do when taking a picture is open the shutter and hold it open. Then I take the photo by triggering the microscope light with a darkroom timer or use the leaf shutter on the MIKAS. I run into the same problem using high power telephoto lenses. What is worse than the shutter shake is the movement of the mirror on SLR cameras. That's why a feature added to SLR's was a mirror lockup. A good sturdy tripod helps too.

One big improvement since digital cameras took over is the quality of the lenses. Even a cheap lens made today can be much sharper than lenses made in the film era. Comparing digital Megapixels to film is kind of like comparing apples and oranges. There are other factors with film that affect the sharpness like film grain. I try to use a very fine grain film which translates to a slow film like Ilford Pan-F 50, Panatomic-X or TMax 100.

Since it's so easy to zoom in on photos these days that probably helps drive the necessity for better lenses. That's probably especially true on a forum of microscope enthusiasts. Zooming in on my film photos would be disappointing but I intend them to be viewed as a whole. I'm still learning how to do photomicography so hopefully there will be improvement. There are other limitations to overcome like chromatic aberration and a very shallow depth of field. I am always impressed with focus stacked shots shared on this forum but that would take a whole roll of film to make one photo with film. Maybe I'll try that someday. I understand there were some darkroom techniques that were similar to focus stacking but they appear to be quite difficult.

Thanks, folks, for the illuminating comments!