19 December 2005

New year (well, almost), new camera

I couldn't wait for Santa (I've been a naughty boy anyway) and bought myself a new camera, this time a digital SLR, the new Olympus E-500. Besides the 2 lenses that come with the camera as a kit, I also got a Zuiko 35 mm macro lens. Here is my meager review of the macro lens with some test shots I have taken with it.

My test object was a stage micrometer (Edmund Optics NT36-121), which is an etching of a millimeter (1000 μm) divided into 10 μm*. The picture below shows a photograph of the micrometer taken thru an Olympus SZ60 stereomicroscope. The 10-μm lines are clearly resolved.



Below is a photograph of the same using the E-500 with the 35 mm macro lens at its highest (or almost highest) magnification. Admittedly, the micrometer is not a good photographic subject, because the etching is very faint and, therefore lacks contrast. The photo on the left (A) is the original, while the one on the right (B) is after I increased its brightness and contrast in Photoshop (I did not change the sharpness).



The macro lens can't resolve the lines 10 μm apart; the closest lines it can resolve are about 50 μm apart. That is not bad at all when we realize that this is not a microscope. And I think the image quality is pretty good for a camera lens at such a high magnification.

The alternating blue and red lines visible in the background of Fig. B are known as Newton's rings. They are not an artifact of the camera, but are formed on the micrometer itself. Newton's rings are interference patterns created when 2 glass surfaces are pressed against each other (the micrometer is on a microscope slide under a thin cover glass).

When taking such highly magnified pictures the camera must be on a tripod or some other support. Otherwise, no matter how steady your hands are, the image will be blurred, because even the movements that may be imperceptible to you are magnified by the lens. This makes it somewhat impractical to use the camera for taking extreme close-ups in the field unless a tripod is available and the thing you intend to photograph is stationary. The picture below shows the set-up I used to photograph the micrometer.



A: homemade copy stand; B: E-500 with macro lens; C: spirit level; D: camera remote; E: rack & pinion mechanism from an old microscope used for fine focus; F: glass plate to hold transparent objects to be copied (negative, slide, etc.); G: very heavy, shot filled base; H: light source (originally for HP scanner shown on the left); I: screw into the camera's tripod socket (it all depends on that screw!).

I use the spirit level to assure that the camera and the object that is being photographed are both horizontal. Also, the shutter should be released with a remote especially if the shutter speed is slow. An additional potential source of vibrations is the movement of the mirror inside the camera, but that is harder to deal with.

I will review the camera itself on another post.


*This micrometer is used mainly to calibrate microscope eyepiece reticles. It would be impractical to use for direct measurements.

6 comments:

pascal said...

Does the camera have mirror lock-up? Most SLRs have a way to lock the mirror up with the first button push and opens the shutter with the next push.

Anonymous said...

You might get better resolution if you use the camera in the black&white mode. (At least that happens when you try to photograph the full moon.) Change the camera settings to BW and rephotograph the micrometer stage. Also, what was your aperture setting? All lenses have "sweet spots". You might try different apertures and observe the results.

Roger B. said...

I found that post very interesting because I'm currently considering buying an Olympus E-500.

According tone member of the Flickr E-500 Users Group "You can also lock the mirror up for 2 or 10 seconds before the shutter fires to lessen vibration more. Also you can enable noise reduction for long exposures."

Is it possible to use of cable release instead of the infra red remote? The sensor seems to be in a potentially awkward position.

AYDIN ÖRSTAN said...

The folks at Olympus know how to make good cameras, but they don't know how to write good manuals. The manual doesn't mention locking the mirror, or if it does, it is probably buried in a footnote somewhere. The words mirror, lock, vibration are not in the index. I'll keep searching.

No, you can't use a cable release. Even the most recent film SLRs had done away with cable releases.

AYDIN ÖRSTAN said...

OK, found it. It's under "anti-shock", which should have been called anti-vibration & the relevant keywords should have been in the index.

Anyway, yes the mirror can be locked any number of whole seconds between 1 to 30s.

I will soon redo my resolution test & post the results.

Roger B. said...

I went ahead and bought an E-500 yesterday - I got a very good deal.

The camera seems very impressive, but I agree that the manual is not as user-friendly as it could be. It would be useful to have a 'field guide' like the ones that have been published for the Nikon D70 and D50.