Quality expectations through an Olympus SZ40?

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RBack
Posts: 6
Joined: Sun Jan 11, 2015 4:37 am

Quality expectations through an Olympus SZ40?

Post by RBack »

Not entirely sure If I'm posting this in the proper section but anyway... here it comes.

Got myself an Olympus SZ4045TR stereo microscope a while ago. The main reason for this purchase was because I was in need of one due to working with insect illustrations (habitus drawings). It works very well for that purpose.

But since it has got the phototube and since I'm doing some macro photography as well, I thought that I had to try it out. So I also got myself the proper adapters and a photo eyepiece.

After the first tests I noticed that the results are far from as good as the ones I get with the auto bellows and a El-Nikkor 50mm f2.8.
But that's thats probably only natural and expected.
However I was interested in the greater enlargement possibilities of the microscope. I wasn't expecting flawless results but I was expecting slightly more that I have gotten so far.

Images comes with lack of contrast and the sharpness is simply not enough.
So my question is... are the images below of typical quality for this equipment? Or am I missing something? Blur due to motion shouldn't be a problem - or at least that's what I think. The image is shot raw and unretouched before saved as jpeg in this example. I can of course squeeze out both some contrasts and a bit of sharpness but the "raw material" is not satisfying anyhow.
(well, I've always been planning on getting a microscope objective/lens for the bellows anyway).

Equipment:
- Canon 60D
- Olympus SZ4045TR with SZ-PT phototube, Photomicro L Adapter
- Olympus NFK 2.5x LD 125 Photo eyepiece.
Light: Two Airam Airaflood 10w led-lamps (720 lumen) with one layer of white baking paper as diffusor.

Image: Same image - as from the camera. Uncropped and 100% detail.
Shutter time: 0"8
ISO 100
Aperture is to me unknown, but depth of focus is rather high and the ridiculously big amount of dust on the sensor is depicted nice and sharp ;)
The short wing beetle is maximum 1 mm long.


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rjlittlefield
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Post by rjlittlefield »

RBack, welcome aboard!

I looked for but did not find information about the aperture on that scope. There is a brochure with quite a bit of information at http://www.alanwood.net/downloads/olymp ... ochure.pdf, but on quick scan I don't find in it anything about aperture.

I agree that your sample image looks washed out and not very sharp. In principle, those two problems will have different causes, for example contrast being reduced by flare, but sharpness being reduced by small aperture.

I have a couple of suggestions that may help tease out what's going wrong.

1. Regarding the loss of contrast, I suggest to remove your camera from its mount on top of the microscope, then place your own eye at the same place where the sensor would have been. Of course you will not see a focused image of the subject, but if there are for example reflections from the sides of the adapter tube, you should be able to see those easily. If you have a small camera such as a cell phone or webcam, then placing its lens at the location of the DSLR's sensor can let you take a picture of what's happening, to share with us and to document improvements such as added flocking or baffles.

2. Regarding resolution and aperture, I suggest to take pictures of the same beetle under similar lighting conditions, using your EL Nikkor 50 mm f/2.8 at a variety of aperture settings. DOF is tied directly to the working aperture, so if you can get matching out-of-focus appearance with the EL Nikkor and the SZ4045TR, you'll know the aperture of the microscope.

--Rik

RBack
Posts: 6
Joined: Sun Jan 11, 2015 4:37 am

Post by RBack »

Many thanks for your reply!
The excellent website that Alan Wood has put together, has been one of my www-whereabouts rather often during the last two months.

Based on your suggestions, I've been taking a closer look.
There are indeed reflections inside the photo tube. I didn't yet take a picture to illustrate it, but surrounding the small, bright field of view, is a quite wide circle of clearly visible extra light. The Photomicro L Adapter has got an narrow opening in its lower end - like an unadjustable aperture ring. However it would need to be smaller still in order to screen off the light reflections. It would be easy to make the hole a bit smaller - with a bit of non transparent tape - and make new test photos.

The effective aperture is, I'm afraid, not possible to change.
However I'll go on and at some point I'll surely try to check out what aperture it equals.

Some days ago I did a few tests with an Ectemnius wasp. The El-Nikkor was at f5.6 and here are two quite comparable, unretouched images.
First the El-Nikkor. Actually I was just trying some light that day... and then I did the same thing through the microscope some days later when an OM-EOS adapter finally arrived (same light in both).
I haven't calculated the effective aperture of the El-Nikkor at full (about 17 cm) length of the bellows (might it be somewhere around f20?) and the microscope aperture is smaller still. DOF is much wider.

Edit: Magnification rate is of course smaller in this one than in the image of the first post. The Ectemnius head is 3.8 mm wide.

/Robert

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