Tomioka Tominon 17mm f4 (17TT)

[ray_parkhurst]

I just pulled out a Tominon 17mm f4 lens I bought as part of a full set that was used with the Polaroid MP4 system. The lenses are generally very good, though the 135 and 105 are middle of the road in quality. The 75 is very good, a bit better than a 75ELN, while the 35 is even better and covers up to 5x well. I generally don't go beyond 4-5x, as that covers the "money shot" for Lincoln RPMs where the entire date and MM can be captured in a single frame. But since the Tominons seem to keep getting better as focal length shortens, I thought I'd try the 17 at minimum magnification to compare. As it turns out, the 35 is good wide open, and the 17 follows the same trend. At f4 it looks excellent, and is sharp enough to require a 6-image stack. Here is an example image using the 17TT at the lowest magnification I can achieve on the bellows:

http://i943.photobucket.com/albums/ad273/rparkhurst/New-Out723_01.jpg

The 17TT has three problems:
1) It has a built-in extension that I suppose is designed for parfocality with the 35TT, but limits the minimum magnification to around 6x
2) It uses the Copal-1 shutter thread (M40x0.75) so requires an adapter
3) Working distance is pretty small since the focal length is so short

[seal006]

Absolutely stunning. I do wish I had you as photographer for my website. My sales would skyrocket.

[Scott99]

Now THAT is pretty close to perfect. I love how clear the picture is.

[jcuve]

Nice. I was looking for something smaller to get closeups in some hope of not shooting through my scope anymore. I was looking at some 28mm lenses. This particular 17mm is really nice, great shots Ray. Have you tried any of those microscope objectives in 4x or so?

[ray_parkhurst]

Nice. I was looking for something smaller to get closeups in some hope of not shooting through my scope anymore. I was looking at some 28mm lenses. This particular 17mm is really nice, great shots Ray. Have you tried any of those microscope objectives in 4x or so?

I've tried a fair number of microscope objectives from 2x-10x. Not the really expensive ones like the Nikon CF Plan Apo 4x NA 0.2 since I have not even been able to locate one, but I have tried several other Nikons and had good luck with them. I also tried some generic Plan and Semi-Plan Achromats from China and had good luck with them. I published a comparison back in February of this year comparing the 4x objectives I had on hand:

http://www.lincolncentresource.net/forums/showthread.php?t=19718

Since then I have purchased some better Nikon Plan 4 that are a bit better than the one published previously.

I think you will find that most decent objectives will outperform a general-use macro lens since they can be specifically optimized for a particular magnification. Plus the microscope objectives are optimized for use wide open.

A few formulas of interest:

feff = M/2NA = finf(M+1) or NA= M/2feff

For the 17TT, operating around magnification of 6, feff = 4(6+1) = 28, so NA = 6/56 = 0.11, which is so-so for a 4x objective and fairly poor at 6x. So you can do much better with a simple 4x NA=0.1.

All that said, the result is actually quite good for the 17TT, much better than I expected.

[wapa]

Very nice Ray! Well done.

[jcuve]

I missed your objective study thread. Funny, I was just looking at 4x no name objectives that were PLAN thinking to try one out...

[Roller]

Are you talking about adapting a microscope objective to bellows? If so, how migh that be done?

[jcuve]

Are you talking about adapting a microscope objective to bellows? If so, how migh that be done?


You can buy various adapters which connect to the objective with a mount that has M42 threads, that could then be married to an adapter to fit on a bellows for your camera. I have yet to do it, so there may be a caveat somewhere I am missing. eBay has an assortment of adapters that probably could, one way or another, accommodate just about any objective. I am working in trying it...

[Roller]

You can buy various adapters which connect to the objective with a mount that has M42 threads, that could then be married to an adapter to fit on a bellows for your camera. I have yet to do it, so there may be a caveat somewhere I am missing. eBay has an assortment of adapters that probably could, one way or another, accommodate just about any objective. I am working in trying it...
I think you are shooting with a Nikon as well Jason. I'd like to know what you have found as an adapter, when you do find one. Also, are you attempting to adapt a stereo microscope objective or on intended for transparencies?

[jcuve]

I think you are shooting with a Nikon as well Jason. I'd like to know what you have found as an adapter, when you do find one. Also, are you attempting to adapt a stereo microscope objective or on intended for transparencies?

I have a Canon. I am angling to take a Plan objective (meant for a microscope) with a RMS mount and connect it to an RMS to M42 adapter and then connect that to a M42 to EOS adapter. Some objectives have weird mounts and you have to figure out what threads it has.

[ray_parkhurst]

You can buy various adapters which connect to the objective with a mount that has M42 threads, that could then be married to an adapter to fit on a bellows for your camera. I have yet to do it, so there may be a caveat somewhere I am missing. eBay has an assortment of adapters that probably could, one way or another, accommodate just about any objective. I am working in trying it...

Here's a Nikon P4/0.1 ($25 on eBay) shooting that same Cent:
http://i943.photobucket.com/albums/ad273/rparkhurst/New-Out726_02.jpg

And the same objective with longer extension, beyond its optimum 4x but still quite good:
http://i943.photobucket.com/albums/ad273/rparkhurst/New-Out99992_01.jpg

These were shot with the objective mounted to the cone-shaped adapter sold here:
http://www.ebay.com/itm/RMS-Thread-to-M42-Adapter-for-microscope-objective-cone-/350352400700?pt=US_Lens_Adapters_Mounts_Tubes&hash=item5192a1613c

Adapter mounted on Pentax Auto Bellows, Canon XS

[Scott99]

Very nice! The first image I said was close to perfect, but this one has to be my idea of perfect. Everything in focus, nothing too bright, very few parts too dark (tops of the numbers), and the entire view is illuminated adequately.

[jcuve]

I'm going to try an objective and ordered some equipment. I am concerned I won't get the lighting I prefer if the working distance is not all that great...we'll see what happens in a few weeks once it is all together.

[ray_parkhurst]

All I can say about lighting at these close working distances is "ping pong ball". Drill a hole, cut in half, mount on the objective, shine a Jansjo or two at it and away you go. Ray