Will it Vignette?
I have tried my 400mm 5,6 Canon tele objective on my microscope - it does not vignette at f 5.6 with a microscope objective - I have tested with some Nikons and Mitutoyos. Stopping down the rear lens causes vignetting, easily noticeable at f10.
OFN on Nikons are 25mm so I guess that I can use a 360 mm lens and still get a god picture all the way to the corners on a FF sensor.
I am considering to buy a 360mm f9 enlarger lens (Ronar or Gerogon) and use it as a tube lens, but before I do I would like to know if any one knows if they will Vignette on a FF sensor.
Regards Jörgen
Will it vignette?
Moderators: rjlittlefield, ChrisR, Chris S., Pau
- rjlittlefield
- Site Admin
- Posts: 23626
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
It is very unlikely that the enlarger lenses will vignette. At 360 mm focal length and f/9, their entrance pupil diameter will be 40 mm diameter. The entrance pupil will probably be located near the center of the lens, only a few cm back from the front surface. This combination of a large entrance pupil, close to the objective, means that the tube lens is very unlikely to block any light that gets through the objective.
--Rik
--Rik
-
- Posts: 3439
- Joined: Sat Nov 20, 2010 10:40 am
- Location: Santa Clara, CA, USA
- Contact:
- rjlittlefield
- Site Admin
- Posts: 23626
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
True enough.JH wrote:Guess the only way to be sure is to buy one and do some testing.
Personally, I'm not very worried about aberrations in the tube lens, considering that sticking a Mitutoyo objective in front of a 360 mm tube lens will stop it down to about f/32 (or narrower, for objectives at 20X and above).
--Rik
Two test pictures with a 40x lens at
http://www.photomacrography.net/forum/v ... hp?t=31211
No problems with corners or colors.
I also did some testing with other lenses. To my surprise the Canon macro photo lens 35mm works quite well with this tube lens. But it does not have the same resolution as a 10x Na 0.3.
Regards
Jörgen
http://www.photomacrography.net/forum/v ... hp?t=31211
No problems with corners or colors.
I also did some testing with other lenses. To my surprise the Canon macro photo lens 35mm works quite well with this tube lens. But it does not have the same resolution as a 10x Na 0.3.
Regards
Jörgen