Nikon PLAN objectives with irises

[DumbMarine]

Does anyone know if Nikon Plan objectives (two with irises) have any practical use in photomicrography?

I must have had an itchy trigger finger and bought a set of PLAN 1.2, 2, 3 and 4 objectives off eBay.

I am set-up for both infinity and 210mm tube usage but know very little about them?

Any responses gratefully recieved.

Ian

[DumbMarine]

I now have received these objectives. Three have irises. I hope the images can serve so that an expert in here can shed some light on these and if they are useful or useless to me?

In anticipation - Thanks!

http://www.photomacrography.net/forum/u ... ics1_2.jpg

http://www.photomacrography.net/forum/u ... ics2_2.jpg

http://www.photomacrography.net/forum/u ... ics3_1.jpg

http://www.photomacrography.net/forum/u ... ics4_1.jpg

[Pau]

Because they are old style pre CF series I guess that they will need complementary correction at the eyepiece, so if I'm right they will perform well in a microscope with the matched Nikon eyepieces from the same era, while in a bellows setup (direct projection on sensor) they will show lateral chromatic aberration outside of the image center. The microscope tube lenght is not specified, so I guess that probabily it will be 160mm like in most finite microscopes (150mm from the objective shoulder to the primary image). But being low power objectives you could get shorter or longer without much trouble, vignette aside.
The parfocal distance when mounted in a microscope (from the focused specimen to the objective shoulder) is likely shorter than the DIN standard (45mm), maybe 37mm.

Because you already have the objectives, test them and please tell us its utility.

PD: If after testing you don't find the 1.2X useful for your intended purpose, drop me a pm, I could be interested on it.

[Ichthyophthirius]

As Pau said, these are pre-CF Nikon objektives from the 70s. According to the catalogue, they have to be used with the HK or HKW compensating eyepieces. The HKW 10x high eyepoint, compensating, widefield eyepiece was commonly used for microphotography at the time. The projection eyepiece 3.2x might also work (not sure if it is compensating).

The Plan 4 should have the normal parfocal distance (36.65mm), but the Plan 1.2 - 3 have longer parfocal distances; see working distances here:


Information from p. 22 http://micromundos.dyndns.org/manuals/N ... 201976.pdf

Regards, Ichthy

[DumbMarine]

Thanks to both responders.

I guess the moral here is "act in haste repent at leisure"

Not sure these will perform as hoped if they need these 'compensating' eyepieces.

However thanks for the information as I could discover nothing.

Does anyone know what the iris was for and if that is any use in stacking?

cheers
Ian

[Ichthyophthirius]

... no reason for remorse, I think.

I think they were designed especially for microscope photography. The irises are perfect for stopping down and controlling the NA, i.e. "contrast" and depth of field. The working distances are good as well.

Just try them out and see how their performance compares to newer objectives.

For staking, mount them on a normal 160mm microscope, and take images through a Nikon HK(W) eyepiece using an appropriate camera objective. There is no reason why they should perform worse just because you're observing through eyepieces (that was the case in all the top manufacturers until the 1990s).

I'd be very interested to know how they perform. Please let us now!

Ichthy

[DumbMarine]

Thanks Ichthyophthirius (and that is not easy to pronounce),

My intention was to mount on a bellows or infinity focused lens (Sigma 150mm macro). I don't have a microscope though I would like one. I will certainly post how I get on though this will not be for some time.

I guess I can use software to reduce any chromatic aberrations somewhat though this would have to be done in batch for a large stack.

I really appreciate the help and information from you and other forum members. Everyone is very kind.

regards
Ian

[Edward Ruden]

Thanks to both responders.
Does anyone know what the iris was for and if that is any use in stacking?
Ian

The purpose of the iris is to vary the numerical aperture of the objective. There is a trade-off in photomicrography between depth of focus and resolution as determined by the NA. You'd generally want to leave it fully open for stacked imaging and just use a small step. However, for very deep objects (like anterior views of insects), that might result in several hundred steps and narrow focus bands that can confound the software. You might want to stop it down then.

The iris is very useful for live shots of moving subjects, which cannot be stacked. If you stop it down all the way, you won't get good resolution, but at least more of the bug will be in focus. Lateral CA due to not using correcting optics may also not be an issue if the color fringing scale length falls below your ability to resolve it anyway.

Click these links to learn more about Numerical Aperture and Resolution and Depth of Field and Depth of Focus

[Charles Krebs]

I think you will find then useful. I had a couple of these some years ago. The one I found most useful was the 3X. Even when used on a microscope with a 2.5X photoeyepiece, I was able to get some good images.

Here are a few I had posted back some time ago:
http://www.photomacrography1.net/forum/ ... php?t=2048 (3X)
http://www.photomacrography1.net/forum/ ... php?t=2725 (3X)
http://www.photomacrography1.net/forum/ ... php?t=4869 (3X)

One reason I got them was the allure of the iris mechanism. In actual use, the diffraction loss from stopping down the aperture was very obvious, and they were thus only used "wide open". I used them on a microscope and never directly on a bellows. The 1.2X and 2X would likely give better results used on a bellows at their specified magnifications. When used with a 2.5X photoeyepiece on a microscope they yielded on-sensor magnifications of 3X and 5X which was too much magnification for their low NAs. I could do better with "conventional" macro equipment, so I never really used them much. (I also seem to remember that the 1.2X I had seemed to have some optical "issues" so it was perhaps not representative of what the objective is capable of doing).

After I got an Olympus 2/0.8 FL and a 4/016 Plan Apo there were not used much any more.