www.photomacrography.net :: View topic - Raynox DCR-150 tube assembly with flocking
www.photomacrography.net Forum Index
An online community dedicated to the practices of photomacrography, close-up and macro photography, and photomicrography.
Photomacrography Front Page Amateurmicrography Front Page
Old Forums/Galleries
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Raynox DCR-150 tube assembly with flocking
Goto page Previous  1, 2, 3, 4, 5, 6, 7
 
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Macro and Micro Technique and Technical Discussions
View previous topic :: View next topic  
Author Message
rjlittlefield
Site Admin


Joined: 01 Aug 2006
Posts: 20490
Location: Richland, Washington State, USA

PostPosted: Thu Feb 06, 2020 6:56 pm    Post subject: Reply with quote

Ultima_Gaina wrote:
The 10mm segment has no flocking and the same diameter as the other tubes. I remember having tried the FF camera before (with the 10mm segment included) and there was no vignetting.

I expect the other tubes are flocked, and I can see a rough edge on the vignette consistent with flocking.

It is the absence of flocking on the 10mm tube, leaving a larger clear diameter, that makes the vignette go away. The extra extension does give some more magnification, but if the extension were flocked also, giving a smaller clear diameter, the vignette would still be there.

If I had this problem and I wanted to work at large NA where the extra extension could be problematic, then I would remove a 10 mm strip of flocking around the end of the 50mm tube, and omit the extra extension.

--Rik
Back to top
View user's profile Send private message Visit poster's website
Ultima_Gaina



Joined: 28 Jan 2017
Posts: 108

PostPosted: Thu Feb 06, 2020 7:24 pm    Post subject: Reply with quote

rjlittlefield wrote:
Ultima_Gaina wrote:
The 10mm segment has no flocking and the same diameter as the other tubes. I remember having tried the FF camera before (with the 10mm segment included) and there was no vignetting.

I expect the other tubes are flocked, and I can see a rough edge on the vignette consistent with flocking.

It is the absence of flocking on the 10mm tube, leaving a larger clear diameter, that makes the vignette go away. The extra extension does give some more magnification, but if the extension were flocked also, giving a smaller clear diameter, the vignette would still be there.

If I had this problem and I wanted to work at large NA where the extra extension could be problematic, then I would remove a 10 mm strip of flocking around the end of the 50mm tube, and omit the extra extension.

--Rik


I shaved off 5mm and the vignetting is gone (with 3mm it was still there)!

Rik, hats off! This is perfect now!

You are the best!

Back to top
View user's profile Send private message
rjlittlefield
Site Admin


Joined: 01 Aug 2006
Posts: 20490
Location: Richland, Washington State, USA

PostPosted: Thu Feb 06, 2020 7:42 pm    Post subject: Reply with quote

Excellent -- I'm very happy to hear that it's working well for you now.

One thing to keep in mind for future use: some vignette may return if you move the objective farther away from the tube lens, or if you use an objective that provides an effective aperture that is much wider than the f/22 that you're using now.

The reasons are different in those two cases. If the objective is moved farther away from the tube lens, then the exit pupil of the combo moves farther out also. This causes the light cones that construct the corners of the image to become more parallel with the optical axis, so the shadows of the flocking will move inward and may reach the corners of the frame. If you use a wider aperture, then the outermost rays of each cone for the corners of the image will be more parallel to the optical axis, so those rays may get blocked.

A reasonable approach in both cases would be to shave off some more mm of thick flocking. But I wouldn't do that until I saw a problem.

--Rik
Back to top
View user's profile Send private message Visit poster's website
santiago



Joined: 25 Sep 2018
Posts: 109
Location: Nijmegen, The Netherlands

PostPosted: Sat Mar 28, 2020 9:47 am    Post subject: Reply with quote

Great posts on this topic lately, a lot of good info Smile
_________________
Santiago
Flickr
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Macro and Micro Technique and Technical Discussions All times are GMT - 7 Hours
Goto page Previous  1, 2, 3, 4, 5, 6, 7
Page 7 of 7

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group