Hello everybody,
i'm going to make this setup: componon-s 5.6/100 at infinite (rear lens) to componon 4/28 front lens. I can make this, just with a coupling ring to couple them, or, I can put an extension tube between them, if I want to high the magnigication; are all this correct?
I will appreciate every comment to improve up my idea.
Thanks a lot.
Daniele
Setup for coupling enlarge lens
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Re: Setup for coupling enlarge lens
hi Daniele,
I suggest you spend some time on Roberts website, he did a lot of tests with coupled lenses and has many very good pictures which shows his setups:
https://www.closeuphotography.com/stacked-lenses
I suggest you spend some time on Roberts website, he did a lot of tests with coupled lenses and has many very good pictures which shows his setups:
https://www.closeuphotography.com/stacked-lenses
chris
Re: Setup for coupling enlarge lens
The behavior of stacked lenses aren't necessarily easy predictions. The distance between the rear principal plane of the object facing lens and the front principal plane of the image facing lens are a significant part of the setup so you are correct in considering the need for spacer elements. With stacks, the principal planes likely play inside each other, thus complicating simplified mathematical expressions. Personally, I just experiment with what I have at hand, and from time to time, magic happens.
Here is an online two lens simulator that can be used to gain some understanding for the complications of stacks -> https://iwant2study.org/lookangejss/04w ... tion.xhtml
As an example for experimentation, I mount an EL-NIKKOR 50mm f/2.8 on a flat Leica to M43 adapter (which would be counter to practical thought) and then mount a 20mm Canon Macrophoto directly on the front of the EL-NIKKOR. Aside from having the necessary adapters at hand, there was no reason to think this would amount to anything yet I end up with a very compact system that produces results seen here -> https://www.flickr.com/photos/60839073@N04/51038024067/
Good luck and may the stacks be with you!
Here is an online two lens simulator that can be used to gain some understanding for the complications of stacks -> https://iwant2study.org/lookangejss/04w ... tion.xhtml
As an example for experimentation, I mount an EL-NIKKOR 50mm f/2.8 on a flat Leica to M43 adapter (which would be counter to practical thought) and then mount a 20mm Canon Macrophoto directly on the front of the EL-NIKKOR. Aside from having the necessary adapters at hand, there was no reason to think this would amount to anything yet I end up with a very compact system that produces results seen here -> https://www.flickr.com/photos/60839073@N04/51038024067/
Good luck and may the stacks be with you!
Re: Setup for coupling enlarge lens
"I can put an extension tube between them, if I want to high the magnigication; are all this correct?"
If you mean that you expect to change the magnification by changing the extension between the two lenses, that is not correct. Putting an extension tube between them should have very little or no effect on magnification. If the rear lens is focused at infinity, then the magnification is just the focal length of the rear lens divided by the focal length of the front lens, regardless of the space between them.
You can vary the magnification slightly by changing the extension BEHIND the rear lens.
If you mean that you expect to change the magnification by changing the extension between the two lenses, that is not correct. Putting an extension tube between them should have very little or no effect on magnification. If the rear lens is focused at infinity, then the magnification is just the focal length of the rear lens divided by the focal length of the front lens, regardless of the space between them.
You can vary the magnification slightly by changing the extension BEHIND the rear lens.
Re: Setup for coupling enlarge lens
Yes Chris, I know well the Robert's website, I often check his tests.
Thank you Sym for your suggestions.
Thank you Sym for your suggestions.
That's what I wanted to say. So putting an extension between the 2 lens do not make sense, or can be useful for something? if it is not useful, I will go for buying only the coupling ring.Lou Jost wrote: ↑Tue Mar 21, 2023 8:31 pm"I can put an extension tube between them, if I want to high the magnigication; are all this correct?"
If you mean that you expect to change the magnification by changing the extension between the two lenses, that is not correct. Putting an extension tube between them should have very little or no effect on magnification. If the rear lens is focused at infinity, then the magnification is just the focal length of the rear lens divided by the focal length of the front lens, regardless of the space between them.
You can vary the magnification slightly by changing the extension BEHIND the rear lens.
Re: Setup for coupling enlarge lens
As other commenters mentioned, the distance between the two lenses does make a small and hard-to-predict difference in image quality. But often the smallest distance is the best. I'd start off with that and then play with added rings to see what happens, though Robert O'Toole has done a lot of that work already, so if you can find your combo in one of his tests, it will save you some trouble. Often the changes in distance have different, opposing effects (for example, increased distance can increase CA but sharpen the center).
Re: Setup for coupling enlarge lens
Thanks for your suggestions, much more clear now.Lou Jost wrote: ↑Wed Mar 22, 2023 6:06 amAs other commenters mentioned, the distance between the two lenses does make a small and hard-to-predict difference in image quality. But often the smallest distance is the best. I'd start off with that and then play with added rings to see what happens, though Robert O'Toole has done a lot of that work already, so if you can find your combo in one of his tests, it will save you some trouble. Often the changes in distance have different, opposing effects (for example, increased distance can increase CA but sharpen the center).