Help regarding microscope objective

Cornel · Post by **Cornel** » Wed Feb 08, 2017 12:56 am

Adalbert · Post by **Adalbert** » Wed Feb 08, 2017 2:36 am

Hello Cornel,

You can correct the CA as follows:
http://www.photomacrography.net/forum/v ... highlight=

The second problem is the step-size. The DOF of this lens = 0,0018mm.
So, if you use 3 exp. a DOF then the step-size should be = 0,0006mm.

You also have to minimize the vibrations. e.g. flash with 2sec on the second curtain.

Your tele 200 or macro 105 should focus to the infinity.

BR, ADi

ChrisR · Post by **ChrisR** » Wed Feb 08, 2017 2:41 am

Welcome to the forum!

It's not looking encouraging , but

All pictures are with flash and exposure delay.

You still have the shutter opening and causing vibration.
Try mirror lockup, PLUS a long exposure like 2 seconds, in the dark, with the flash at the end using 2nd/rear curtain sync.

Some cameras, inc some Canons, can start the exposure electrically so there's no wobble. Only the D810 so far can do it of the Nikons, though it's a multi-stage operation.

If you're set up for flash, you should find the room doesn't have to be all that dark.
A short flash duration, 1/4 power or less, also helps.

Good luck. Several of us have been there...

Make sure your camera lenses are at infinity.

Edit - Ah, Adi got in first while I was typing!.

Cornel · Post by **Cornel** » Wed Feb 08, 2017 3:31 am

Thank you for the answers.
The lens is at infinity.
I will try flash at second curtain, I thought at it then but couldn't find the setting in the menu, a google search shows that it's a button combination to activate it. I will post my findings.

I would have like to find out if the lens is ok so I can at least resell it if I bite off more than I can chew.

Lou Jost · Post by **Lou Jost** » Wed Feb 08, 2017 5:58 am

That is a lovely bee!

abpho · Post by **abpho** » Wed Feb 08, 2017 6:02 am

Have you examined the new microscope objective lens? I ran into a problem once where the lens "looked" find under normal examination, but when I shone a bright light onto the lens at a certain angle I could see that the lens was indeed defective. Good luck.

Great looking bee by the way.

Adalbert · Post by **Adalbert** » Wed Feb 08, 2017 8:51 am

Hello Cornel,
I wouldn't bet on it, that something is wrong with this lens. It seems to be OK.
For the taking of my photographs I used a tele 200m or a macro 100mm as a tube-lens, LED-illumination, a relatively large shutter speed, 2 photos a DOF and a thick diffuser.
What about you?
I would suggest that you take photographs from a plan object in order to check the lens.
I think that the errors in your photographs don’t have anything to do with the lens (but probably something with the stacking).
I could imagine that the range was too small and you used too large step-size.
BR, Adi

ChrisR · Post by **ChrisR** » Wed Feb 08, 2017 10:14 am

I'm thinking that if it were step size or stacking, then something, somewhere, would be sharp.

Adalbert · Post by **Adalbert** » Wed Feb 08, 2017 10:54 am

Hello Chris,
OK, maybe some vibrations or reflections from the background?

We also could take a look at the single image taken by the usage of the flash with 1/64 or 1/128 of the power.

If no one was sharp, then I would believe that something is wrong with the lens :-)

BR, ADi

Charles Krebs · Post by **Charles Krebs** » Wed Feb 08, 2017 3:39 pm

I would definitely try something already suggested... rear curtain flash sync.
I am not familiar with your particular camera. If you have a mirror lock-up provision use that as well. Use a shutter speed of about 3 seconds with the flash at the end.

If that doesn't help then there may be an issue with the optic, but at 50X all vibration really need to be eliminated.

(I really doubt this would be the issue, but how close do you have the flash head to the subject, and are you using diffusers? How is the subject mounted? What flash unit is it and and the power level used? Occasionally a direct flash too close to the subject at a fairly high power level can actually move a lightweight or loosely mounted subject during the flash duration.)

Cornel · Post by **Cornel** » Thu Feb 09, 2017 2:05 am

ChrisR · Post by **ChrisR** » Thu Feb 09, 2017 5:09 am

I'd be surprised if that's the (only) problem.
I have objectives which are scratched, etched and chipped.

Only the ones which are "etched" all over, as though they'd been sand-blasted, are poor.

See http://photomacrography.net/forum/viewtopic.php?t=9612

Adalbert · Post by **Adalbert** » Thu Feb 09, 2017 7:32 am

Hello Cornel,

”The pictures posted are single frames, not stacks!”

OK, then I would check the stability of the setup and influence of the external vibrations.
Please show us some photographs of the millimetre paper taken in the darkness with 2 or 3 sec. shutter speed on the second curtain with the lowest power of your flashes.
BR, ADi

Cornel · Post by **Cornel** » Wed Feb 15, 2017 1:23 am

rjlittlefield · Post by **rjlittlefield** » Wed Feb 15, 2017 1:51 am

I don't know any 50X fly eyes, but here is a 20X that includes full frame plus an actual pixels crop (from only 6.3 megapixels).

http://www.photomacrography.net/forum/v ... php?t=7373

I think that fly is a little smaller than yours, but even your fly should have lots of detail that is small enough to need all the resolution that a good objective can deliver.

Your images look like complete mush compared to what they should look like. I think something is seriously wrong with that objective.

--Rik

Edited to add: HERE is a dragonfly eye. The objective was only 10X, but the image shown is cropped to about 1 mm wide so effectively it's about 20X, still only NA 0.25. Again, your objective looks like mush in comparison.