There's no fool like an old fool!

[rjlittlefield]

I'm not sure how Rik would feel about my supplying adapters made by my pal on a non-profit basis via this site.
If there are no objections I'll come back to you in a day or so.

No objections at this point -- just keep it low key and handle any negotiations outside the public forum. If you can just link to an external web page, that would be best of all.

--Rik

[vendav]

Rik,
Thanks, there's no way I'm looking to start a business, just help out those who cannot find this particular adapter elsewhere.
Is it OK if I give my email address and ask that people contact me via that medium, outside this site.
David

[rjlittlefield]

Is it OK if I give my email address and ask that people contact me via that medium, outside this site.

Sure. Or for members, remind people that pushing the "email" button at the bottom of your posting will let them write and send you an email through the forum software. Either way, you receive an email that contains the address of the sender, so you can carry on the conversation completely outside photomacrography.net.

--Rik

[PauloM]

Excuse me for highjacking this thread, but while thinking about the best way to couple a BD objective to a bellows, a question arose:

Assuming such a contraption could be made, how useful would it be to have an adapter for the BD objectives that actually allowed the use of the light "channels" present in those objectives?

Would there be any advantage over the already available LED flash rings that fit on a standard RMS objective?

Has anyone given this idea a thought?

Cheers,
Paulo

[ChrisR]

Has anyone given this idea a thought?

[vendav]

Good morning all,

Ref. the above, if you have any requirement for a "special" adapter please email me and I'll see what my pal can do to help.
I would expect any thread to thread adapter to be possible, but no bayonet fittings - he doesn't have a mill.
Please note that this is intended for one offs, or at most a couple or so adapters of any one type, we are not looking to supply large quantities in a business capacity, life's too short.

David

[PauloM]

@David,

Since you (wisely) don't display your email on your profile, I left you a Private Message here in the forum.

@Chris,

That's very much like what I had in mind. You're way ahead of me...
Have you been able to put that gizmo to good use? Mind telling us where those LED strips came from? Share your experiences with it?

Cheers,
Paulo

[ChrisR]

>Have you been able to put that gizmo to good use?
Not really

>Mind telling us where those LED strips came from?
Ebay

>Share your experiences with it?
Dim (I covet my neighbour's Audi headlight)
Light direction is OK/can be manipulated, but an "led" spectrum.
Works with short Working Distance objectives.
Specular highlights seem to get worse the more you magnify, so you get a ring, or a ring of 6 light dots, or whatever.

Without an EPI illumination rig (down through the lens) at say 40x you normally have to use an ELWD lens, with an NA of say 0.5 .
Resolution is about 1 micron, so 40 microns on sensor, which = lots of pixels per dot. A waste.
So a 40x NA 0.8 apo BD should give a sharper pic, but the WD is only 0.8mm
That works, but with the WD that short, I've still been crashing the lens , because interesting things tend to have bumps on them.

I've tried using small flash tubes from disposable cameras, but it's quite hard, and a string of 300 Volt shocks from the arrangement made me irritable. Mobile phone bits might be more successful.

At 10x, ie as with the lens shown, there's no point that's obvious to me, to do lighting that way. Possibilities in the field, perhaps.

[vendav]

I've now had an opportunity to try the BD infinity objective using a 210mm Eskofot Ultragon process lens as a makeshift tube lens.

If my first attempt at uploading images is successful they will show part of a gnat(?) wing as shot, with just the usual Lightroom enhancements, and a crop at full size.

For comparison I have included a similar pair of images taken with the same objective without the tube lens and a further pair taken with a Nikon Plan 10/0.25 160/- objective.

Also included is a very rough sketch detailing the set up using the process lens.

There is clearly a significant improvement with the tube lens in place and I am pleased with the result. It appears that the infinity objective is quite useful and, to my eye at least, it looks to be just about on a par with the Nikon Plan 10X. Whether it is worth the effort of mounting it on the tube lens is another matter. However, it is good to know that I haven't completely wasted my money!

Kind regards,
David

[rjlittlefield]

Interesting work, David. Thanks for demonstrating that the tube lens actually is needed, and that a generic tube lens can be used with good results.

Oddly, your post got into the forum twice, with about 1/2 hour separation between them. The two posts showed as identical, so I deleted the first one.

--Rik

[vendav]

Hi Rik,

I know that I did it once before, but I'm not guilty of hitting the "submit button twice this time, honest!

Blame the Gremlins.

Kind regards,
David

[rjlittlefield]

The Gremlins have been dutifully blamed.

I just wanted you to know, in case it rang a bell someplace. The 1/2 hour separation was odd -- usually double submissions are only a minute or so apart.

I know that sometimes I leave compositions hanging for a long time while I edit them. After submitting, sometimes I accidentally hit the "backspace" key, which puts my browser back to the composition page. Then I come back after a while, see the composition apparently still in progress, and say to myself "I thought I submitted that, but I guess I was mistaken." So I hit Submit again......only to discover that I now have two copies with quite a while between them.

At least I think that's what happens. Or it could be the Gremlins just having fun with me!

--Rik

[mgoodm3]

I have just been playing around with using a camera lens or enlarging lens as a tube lens for a 4x oly infinity objective I have. My question is that it will likely work best with a tube lens of a similar focal length that it was made for (somewhere around 200 mm for Oly?)?

Seems to work ok with my Nikon 105 as a tube lens, but it needs a fair amount of extension to keep from vignetting.

[ChrisR]

It would be interesting to know if it would work on a normal 200mm lens, such as a 70 - 200 zoom.

Have you found the distance between the scope lens and the relay lens to be important?

[rjlittlefield]

Seems to work ok with my Nikon 105 as a tube lens, but it needs a fair amount of extension to keep from vignetting.

I'm confused.

The concept of an infinity objective is that it outputs bundles of parallel rays. The tube lens sees those as coming "from infinity" and focuses them into a real image. If the tube lens is not focused at infinity, then the objective is not being used as intended. The words "fair amount of extension" suggest to me that your Nikon 105 is focused much closer than infinity, which is taking the objective away from its design point.

Have I misunderstood what you're doing?

Regarding your other question...

The tube lens has to have a large enough clear aperture to capture bundles from the entire field, or you will get vignetting. This problem should be minimized by placing the objective as close as possible to your substitute 'tube lens'. Also by running the tube lens wide open.

To get the rated magnification, the tube lens has to be the correct focal length.

If the objective is expecting aberration correction in the tube lens, then that has to be correct also, but I suspect that's less important than the first two aspects.

--Rik