www.photomacrography.net :: View topic - My MPC 90mm super macro lens
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 
My MPC 90mm super macro lens
Goto page 1, 2  Next
 
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Equipment Discussions
View previous topic :: View next topic  
Author Message
MarkSturtevant



Joined: 21 Nov 2015
Posts: 388

PostPosted: Fri Jan 12, 2018 9:51 pm    Post subject: My MPC 90mm super macro lens Reply with quote

Here I show a "super macro" lens that I had built a while ago. I think it turned out interesting, but this posting is not just to show it to readers here. I would also like to solicit some advice about how I might improve its image quality.
I have dubbed the lens the "MPC 90mm", although it is certainly longer than 90mm. "MPC" stands for "Mark's Personal Contraption". Central components of this lens in its current form is the Pixco 36-90mm helical extension tube and the Neewer electronic reversing ring. The lens is a reverse mounted Canon EF 50mm f/1.8 II. Fitting everything together are a bunch of different adapter rings.


The insides are masked with Protostar paper, although the internal threaded areas of the Pixco helical extension tube can not be masked. I did as much masking as I could, I feel.


At full extension, this lens gets 3.14 :1 magnification on my T5i camera body. Over 4 : 1 if I add extension tubes. It is surprisingly light weight, but that is because most of the components are aluminum. I can use it hand-held easily enough (although extensively propped on things) at less than its full extension. Toward full extension I need a tripod and remote shutter cable. Those who make good use of the famous MP-E 65mm lens have my deepest respect!

Here are some pictures of results.





So in general I am liking but not yet wowed by this lens. I somehow don't feel that it is as sharp as I was hoping (am I imagining that?), and on some occasions it seems to me that the contrastyness is just not there. The 2nd ant picture and the leafhopper picture are examples. These are taken in bright light. For that issue, perhaps I could cut down on internal reflections by mounting a fixed aperture near the 50mm lens? Not sure how to do that.
_________________
Mark Sturtevant
Dept. of Still Waters
Back to top
View user's profile Send private message
Pau
Site Admin


Joined: 20 Jan 2010
Posts: 4529
Location: Valencia, Spain

PostPosted: Sat Jan 13, 2018 1:45 am    Post subject: Reply with quote

Yes, the relative lack of contrast can be due to the unflocked parts of the tubes, I suppose it can't be flocked because the variable length mechanism. A rectangular flare cutting stop placed near the camera side could be more effective than at the lens side.
_________________
Pau
Back to top
View user's profile Send private message
Lou Jost



Joined: 04 Sep 2015
Posts: 2859
Location: Ecuador

PostPosted: Sat Jan 13, 2018 5:19 am    Post subject: Reply with quote

Mark, I think it is still a 50mm lens even though reversed. In what respect do you find that it behaves like a 90mm lens?
_________________
Lou Jost
www.ecomingafoundation.wordpress.com
www.loujost.com
Back to top
View user's profile Send private message Visit poster's website
mawyatt



Joined: 22 Aug 2013
Posts: 1665
Location: Clearwater

PostPosted: Sat Jan 13, 2018 6:53 am    Post subject: Reply with quote

Mark,

Agree with Pau, the 2nd image shows some internals that could reflect. You might be able to remove the adapters and moveable pieces for flocking, then reassemble or use a long loose tube of Protostar or Beetle Black that could slide inside the lens and move with the length changes. If you use the Protostar for the tube leave the paper backing on of course.

The Neewer reversing ring is nice, do you know if they make one for Nikon? Google didn't give me anything positive.

Best,
_________________
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike
Back to top
View user's profile Send private message
ChrisR
Site Admin


Joined: 14 Mar 2009
Posts: 7951
Location: Near London, UK

PostPosted: Sat Jan 13, 2018 7:27 am    Post subject: Reply with quote

You could try black paper discs/rectangles, strategically positioned:

_________________
Chris R


Last edited by ChrisR on Sat Jan 13, 2018 7:28 am; edited 2 times in total
Back to top
View user's profile Send private message
MarkSturtevant



Joined: 21 Nov 2015
Posts: 388

PostPosted: Sat Jan 13, 2018 7:28 am    Post subject: Reply with quote

Pau wrote:
Yes, the relative lack of contrast can be due to the unflocked parts of the tubes, I suppose it can't be flocked because the variable length mechanism. A rectangular flare cutting stop placed near the camera side could be more effective than at the lens side.

Thank you, Pau. I will try to work on that. It seems likely that the remaining internal reflections cause enough problems to be noticable in bright light, and are just not so noticable in lower ambient light.
I thought I read somewhere about putting a rectangular screen near the lens. Do you think doing both -- placing one near the lens and the camera -- will be more insurance, or would that cause a new issue?
_________________
Mark Sturtevant
Dept. of Still Waters
Back to top
View user's profile Send private message
MarkSturtevant



Joined: 21 Nov 2015
Posts: 388

PostPosted: Sat Jan 13, 2018 7:30 am    Post subject: Reply with quote

Lou Jost wrote:
Mark, I think it is still a 50mm lens even though reversed. In what respect do you find that it behaves like a 90mm lens?

I know my silly name for the lens is wrong. The 90mm is from the max extension of the Pixco tube. A better one might be based on measuring the actual length at full extension, from the camera sensor to ...? I don't know really.
_________________
Mark Sturtevant
Dept. of Still Waters
Back to top
View user's profile Send private message
MarkSturtevant



Joined: 21 Nov 2015
Posts: 388

PostPosted: Sat Jan 13, 2018 7:38 am    Post subject: Reply with quote

mawyatt wrote:
Mark,
Agree with Pau, the 2nd image shows some internals that could reflect. You might be able to remove the adapters and moveable pieces for flocking, then reassemble or use a long loose tube of Protostar or Beetle Black that could slide inside the lens and move with the length changes. If you use the Protostar for the tube leave the paper backing on of course.
The Neewer reversing ring is nice, do you know if they make one for Nikon? Google didn't give me anything positive.

Best,

There are some stacked adapters, and maybe I could flock these as a unit. There is not much surface on their inner edges for adhering flocking, but I can look. I had though about making an inner tube of flocking. Either of fixed length or extendable/collapsable (tricky!). What has held me back is some consideration of what could happen out in the field. If the inner tube got loose or out of line while miles away from home I would not have the tools to do a proper fix.

I think there was a different company that very recently came out with the electronic reversing ring for Nikon. I just remember reading about it a couple months ago. The Chinese companies blatantly copy other companies seemingly at will, and we benefit from that. I will look for it.
_________________
Mark Sturtevant
Dept. of Still Waters
Back to top
View user's profile Send private message
Lou Jost



Joined: 04 Sep 2015
Posts: 2859
Location: Ecuador

PostPosted: Sat Jan 13, 2018 8:19 am    Post subject: Reply with quote

Mike, you can easily make one of those yourself for any fully-electronic lens, as I did for my Olympus.
_________________
Lou Jost
www.ecomingafoundation.wordpress.com
www.loujost.com
Back to top
View user's profile Send private message Visit poster's website
mawyatt



Joined: 22 Aug 2013
Posts: 1665
Location: Clearwater

PostPosted: Sat Jan 13, 2018 8:29 am    Post subject: Reply with quote

Lou Jost wrote:
Mike, you can easily make one of those yourself for any fully-electronic lens, as I did for my Olympus.


Lou,

Thanks, yes I recall when you did this. I'm too lazy to actually build one now, got some electronics stuff (Live View EFCS with Flash for Nikon D500 & D850 specifically for stacking with Stackshot & WeMacro controllers, should work with other cameras also) I'm in the mist of designing and building (waiting on parts).

Best,
_________________
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike
Back to top
View user's profile Send private message
Pau
Site Admin


Joined: 20 Jan 2010
Posts: 4529
Location: Valencia, Spain

PostPosted: Sat Jan 13, 2018 9:01 am    Post subject: Reply with quote

Mark, take a look at
http://www.photomacrography.net/forum/viewtopic.php?t=15657
_________________
Pau
Back to top
View user's profile Send private message
MarkSturtevant



Joined: 21 Nov 2015
Posts: 388

PostPosted: Sat Jan 13, 2018 11:15 am    Post subject: Reply with quote

Pau wrote:
Mark, take a look at
http://www.photomacrography.net/forum/viewtopic.php?t=15657

This is useful! So if I can pick up on key points in that thread, an optimal shape for an internal baffle should be circular if near the lens (near the ~ circular aperture), and rectangular if near the rectangular sensor. Is that right?
_________________
Mark Sturtevant
Dept. of Still Waters
Back to top
View user's profile Send private message
Lou Jost



Joined: 04 Sep 2015
Posts: 2859
Location: Ecuador

PostPosted: Sat Jan 13, 2018 11:18 am    Post subject: Reply with quote

And the optimal region for the baffle is near the middle, not near the sensor nor near the aperture.
_________________
Lou Jost
www.ecomingafoundation.wordpress.com
www.loujost.com
Back to top
View user's profile Send private message Visit poster's website
MarkSturtevant



Joined: 21 Nov 2015
Posts: 388

PostPosted: Sat Jan 13, 2018 12:42 pm    Post subject: Reply with quote

mawyatt wrote:

The Neewer reversing ring is nice, do you know if they make one for Nikon? Google didn't give me anything positive.

I tracked down a new brand of these rings, and its shown here: https://www.dpreview.com/news/8356894151/novoflex-introduces-electronic-lens-reversing-system-for-sony-e-mount for Sony. Likely that is what i saw earlier. In any case, it seems one could make one with extension tubes and a cable, as shown here:
http://www.photomacrography.net/forum/viewtopic.php?p=96663#96663

Admin edit RJL: make second link point to specific post.
_________________
Mark Sturtevant
Dept. of Still Waters
Back to top
View user's profile Send private message
Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 3070
Location: Ohio, USA

PostPosted: Sun Jan 14, 2018 1:23 am    Post subject: Reply with quote

Lou Jost wrote:
And the optimal region for the baffle is near the middle, not near the sensor nor near the aperture.
Lou,

To my thinking, the optimal placement for a flare-cut stop is as near as possible to the sensor, in order to place this stop in a location where it will block reflectance from as many flare-inducing surfaces as possible.

But you assert an idea contrary to this. And knowing you, my bet is that solid thinking supports your assertion. Would you mind elucidating it?

Cheers,

--Chris S.
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Equipment Discussions All times are GMT - 7 Hours
Goto page 1, 2  Next
Page 1 of 2

 
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