infinite objective with bellows

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andre reichmann
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infinite objective with bellows

Post by andre reichmann »

it seems an infinite objective with bellows needs an intermediate kind of lens....
i presume this is to correct optically the system ( superficial understanding... :-) )
can anyone point me which lenses of this type i should buy ? i would be using a pb6 bellows that i have, nikon 4x and 10x objectives... maybe in the future mitutoyo 10x...

thanks a lot again for the assistance and help this site / forum gives !!!!

andre

Pau
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Post by Pau »

First take a look at:
http://www.photomacrography.net/forum/v ... highlight=

you may use the search engine for "tube lens"
Pau

andre reichmann
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Joined: Wed Aug 15, 2012 2:40 pm
Location: sao paulo

Post by andre reichmann »

Pau wrote:First take a look at:
http://www.photomacrography.net/forum/v ... highlight=

you may use the search engine for "tube lens"
thks!!!

actually that thread talks about infinite objectives with normal photo lenses as tube lenses and finite objectives with tubes ( without tube lenses ) which i think i do understand...

does not talk about infinite objectives with bellows ....

rjlittlefield
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Re: infinite objective with bellows

Post by rjlittlefield »

andre reichmann wrote:i presume this is to correct optically the system ( superficial understanding... :-) )
Not too superficial. For our purposes this is really the only purpose of the tube lens. In the microscope, the infinity space between the objective and the tube lens provides a place where it is easy to stick filters and beam splitters without degrading the image.
can anyone point me which lenses of this type i should buy ? i would be using a pb6 bellows that i have, nikon 4x and 10x objectives... maybe in the future mitutoyo 10x...
Quite good options are the Raynox close-up lenses as demonstrated by seta666 at http://www.photomacrography.net/forum/v ... hp?t=18145. The DCR-150 at 208 mm will give very close to rated magnification with the tube lens focused at infinity; the DCR-250 at 125 mm will give about 62% of rated magnification, with a correspondingly wider field.

In both cases you can change the bellows length to adjust the magnification somewhat. The combo essentially acts like a finite objective. With the 4X and 10X objectives, good image quality will be maintained over a pretty wide range because of the small NA. As always, pushing down too far will run into coverage problems. Pushing up too far will give empty magnification due to diffraction, and with high NA objectives (NA 0.40 and above) there will also be added aberrations that degrade the image. To make big changes in magnification it is better to use an appropriate tube lens focused at or near infinity.

Other reasonable alternatives include any short-mount lens around 100-200 mm, say enlarging lenses or view camera lenses. Any lens that will focus decently at infinity seems to work well except for zooms at less than full length, which vignette.

If you want to be very formal about it, you can buy an official Nikon tube lens for about $225 plus adapters to match threads. See Edmund Optics, HERE at the Accessories tab. I was lucky to get a Mitutoyo tube lens MT-1 (HERE) for cheap on eBay, but they do not come up very often. It is an interesting lens -- see HERE for test results.

--Rik

andre reichmann
Posts: 55
Joined: Wed Aug 15, 2012 2:40 pm
Location: sao paulo

Re: infinite objective with bellows

Post by andre reichmann »

rjlittlefield wrote:
andre reichmann wrote:i presume this is to correct optically the system ( superficial understanding... :-) )
Not too superficial. For our purposes this is really the only purpose of the tube lens. In the microscope, the infinity space between the objective and the tube lens provides a place where it is easy to stick filters and beam splitters without degrading the image.
can anyone point me which lenses of this type i should buy ? i would be using a pb6 bellows that i have, nikon 4x and 10x objectives... maybe in the future mitutoyo 10x...
Quite good options are the Raynox close-up lenses as demonstrated by seta666 at http://www.photomacrography.net/forum/v ... hp?t=18145. The DCR-150 at 208 mm will give very close to rated magnification with the tube lens focused at infinity; the DCR-250 at 125 mm will give about 62% of rated magnification, with a correspondingly wider field.

In both cases you can change the bellows length to adjust the magnification somewhat. The combo essentially acts like a finite objective. With the 4X and 10X objectives, good image quality will be maintained over a pretty wide range because of the small NA. As always, pushing down too far will run into coverage problems. Pushing up too far will give empty magnification due to diffraction, and with high NA objectives (NA 0.40 and above) there will also be added aberrations that degrade the image. To make big changes in magnification it is better to use an appropriate tube lens focused at or near infinity.

Other reasonable alternatives include any short-mount lens around 100-200 mm, say enlarging lenses or view camera lenses. Any lens that will focus decently at infinity seems to work well except for zooms at less than full length, which vignette.

If you want to be very formal about it, you can buy an official Nikon tube lens for about $225 plus adapters to match threads. See Edmund Optics, HERE at the Accessories tab. I was lucky to get a Mitutoyo tube lens MT-1 (HERE) for cheap on eBay, but they do not come up very often. It is an interesting lens -- see HERE for test results.

--Rik
thks rik
ps; i'll think here a bit... don't wanna spend 225$ for that nikon tube lens :shock:

andre reichmann
Posts: 55
Joined: Wed Aug 15, 2012 2:40 pm
Location: sao paulo

Re: infinite objective with bellows

Post by andre reichmann »

andre reichmann wrote:
rjlittlefield wrote:
andre reichmann wrote:i presume this is to correct optically the system ( superficial understanding... :-) )
Not too superficial. For our purposes this is really the only purpose of the tube lens. In the microscope, the infinity space between the objective and the tube lens provides a place where it is easy to stick filters and beam splitters without degrading the image.
can anyone point me which lenses of this type i should buy ? i would be using a pb6 bellows that i have, nikon 4x and 10x objectives... maybe in the future mitutoyo 10x...
Quite good options are the Raynox close-up lenses as demonstrated by seta666 at http://www.photomacrography.net/forum/v ... hp?t=18145. The DCR-150 at 208 mm will give very close to rated magnification with the tube lens focused at infinity; the DCR-250 at 125 mm will give about 62% of rated magnification, with a correspondingly wider field.

In both cases you can change the bellows length to adjust the magnification somewhat. The combo essentially acts like a finite objective. With the 4X and 10X objectives, good image quality will be maintained over a pretty wide range because of the small NA. As always, pushing down too far will run into coverage problems. Pushing up too far will give empty magnification due to diffraction, and with high NA objectives (NA 0.40 and above) there will also be added aberrations that degrade the image. To make big changes in magnification it is better to use an appropriate tube lens focused at or near infinity.

Other reasonable alternatives include any short-mount lens around 100-200 mm, say enlarging lenses or view camera lenses. Any lens that will focus decently at infinity seems to work well except for zooms at less than full length, which vignette.

If you want to be very formal about it, you can buy an official Nikon tube lens for about $225 plus adapters to match threads. See Edmund Optics, HERE at the Accessories tab. I was lucky to get a Mitutoyo tube lens MT-1 (HERE) for cheap on eBay, but they do not come up very often. It is an interesting lens -- see HERE for test results.

--Rik
thks rik
ps; i'll think here a bit... don't wanna spend 225$ for that nikon tube lens :shock:
would all enlarging lenses in the 100-200mm range work well? nikon ? rodenstock ? schneider ? probably one of these would be small enough to put with a bellows and a mitutoyo....

rjlittlefield
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Re: infinite objective with bellows

Post by rjlittlefield »

andre reichmann wrote:would all enlarging lenses in the 100-200mm range work well? nikon ? rodenstock ? schneider ? probably one of these would be small enough to put with a bellows and a mitutoyo....
Yes, all of the above should work fine. In all the tests I can recall seeing, the differences due to tube lenses seem quite small. This is mainly because the objective stops down the tube lens to around f/20 at rated magnification. Aside from transverse CA, most aberrations due to the tube lens get cut down pretty well at such a small aperture.

--Rik

andre reichmann
Posts: 55
Joined: Wed Aug 15, 2012 2:40 pm
Location: sao paulo

Re: infinite objective with bellows

Post by andre reichmann »

rjlittlefield wrote:
andre reichmann wrote:would all enlarging lenses in the 100-200mm range work well? nikon ? rodenstock ? schneider ? probably one of these would be small enough to put with a bellows and a mitutoyo....
Yes, all of the above should work fine. In all the tests I can recall seeing, the differences due to tube lenses seem quite small. This is mainly because the objective stops down the tube lens to around f/20 at rated magnification. Aside from transverse CA, most aberrations due to the tube lens get cut down pretty well at such a small aperture.

--Rik
great ! let's see if i can find something used in good conditions around here...

andre reichmann
Posts: 55
Joined: Wed Aug 15, 2012 2:40 pm
Location: sao paulo

Re: infinite objective with bellows

Post by andre reichmann »

andre reichmann wrote:
andre reichmann wrote:
rjlittlefield wrote:
andre reichmann wrote:i presume this is to correct optically the system ( superficial understanding... :-) )
Not too superficial. For our purposes this is really the only purpose of the tube lens. In the microscope, the infinity space between the objective and the tube lens provides a place where it is easy to stick filters and beam splitters without degrading the image.
can anyone point me which lenses of this type i should buy ? i would be using a pb6 bellows that i have, nikon 4x and 10x objectives... maybe in the future mitutoyo 10x...
Quite good options are the Raynox close-up lenses as demonstrated by seta666 at http://www.photomacrography.net/forum/v ... hp?t=18145. The DCR-150 at 208 mm will give very close to rated magnification with the tube lens focused at infinity; the DCR-250 at 125 mm will give about 62% of rated magnification, with a correspondingly wider field.

In both cases you can change the bellows length to adjust the magnification somewhat. The combo essentially acts like a finite objective. With the 4X and 10X objectives, good image quality will be maintained over a pretty wide range because of the small NA. As always, pushing down too far will run into coverage problems. Pushing up too far will give empty magnification due to diffraction, and with high NA objectives (NA 0.40 and above) there will also be added aberrations that degrade the image. To make big changes in magnification it is better to use an appropriate tube lens focused at or near infinity.

Other reasonable alternatives include any short-mount lens around 100-200 mm, say enlarging lenses or view camera lenses. Any lens that will focus decently at infinity seems to work well except for zooms at less than full length, which vignette.

If you want to be very formal about it, you can buy an official Nikon tube lens for about $225 plus adapters to match threads. See Edmund Optics, HERE at the Accessories tab. I was lucky to get a Mitutoyo tube lens MT-1 (HERE) for cheap on eBay, but they do not come up very often. It is an interesting lens -- see HERE for test results.

--Rik
thks rik
ps; i'll think here a bit... don't wanna spend 225$ for that nikon tube lens :shock:
would all enlarging lenses in the 100-200mm range work well? nikon ? rodenstock ? schneider ? probably one of these would be small enough to put with a bellows and a mitutoyo....
another "deep " question... is an iris always necessary here with the tube lens ?

i found no short tube lenses around here.... mayube i will go via the raynox path .... so i am thinking if i will need an iris ....

thanks in advcance!

rjlittlefield
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Re: infinite objective with bellows

Post by rjlittlefield »

andre reichmann wrote:another "deep " question... is an iris always necessary here with the tube lens ?
I have not tested specifically with the Raynox, but an iris is not needed with any other tube lens that I've tested. There is no iris in the microscope.

The objective alone will stop down the tube lens to about f/20 at rated magnification, f/10 at half magnification. Roughly speaking, this is the same as you'd get from an iris with 10 mm diameter opening.

--Rik

andre reichmann
Posts: 55
Joined: Wed Aug 15, 2012 2:40 pm
Location: sao paulo

Re: infinite objective with bellows

Post by andre reichmann »

rjlittlefield wrote:
andre reichmann wrote:another "deep " question... is an iris always necessary here with the tube lens ?
I have not tested specifically with the Raynox, but an iris is not needed with any other tube lens that I've tested. There is no iris in the microscope.

The objective alone will stop down the tube lens to about f/20 at rated magnification, f/10 at half magnification. Roughly speaking, this is the same as you'd get from an iris with 10 mm diameter opening.

--Rik
alright, i get it !!!!!
i am already starting to stack now :-) tested my cfi6010x with my nikkor 200mm micro afd with a fly wing( easy to start ... ) and it did work !!!! seems to work with my 300mm f4 nikor at aprox 14x also :-)
in a while i will be ready to start posting i guess :-)
still have to learn/play/and test about playing with the micrometric control and number of shots needed ...
thanks a lot !
sent you a pm about zerene ....

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