www.photomacrography.net :: View topic - Some more questions from a rank amateur
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 
Some more questions from a rank amateur
Goto page 1, 2  Next
 
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
tevans9129



Joined: 30 Nov 2017
Posts: 12
Location: TN

PostPosted: Sun Dec 03, 2017 5:24 pm    Post subject: Some more questions from a rank amateur Reply with quote

Using a Nikon D800e, PB-6 bellows and an old 20mm f/2.8 lens reversed, and if, my calculations are close, 6X with bellows closed and 9X with bellows fully extended…would image quality be better with something like the Amscope 4X, 10X? At this point in time, I am not sure that I would be capable of using more than 10X. All opinions/suggestions are much appreciated. Cost is a factor.

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


Joined: 14 Mar 2009
Posts: 7255
Location: Near London, UK

PostPosted: Mon Dec 04, 2017 3:39 pm    Post subject: Reply with quote

No answer...

My answer, "I don't know" Very Happy

But it should be better. At 10x, even at full aperture, you're very much affected by diffraction. Not accounting for it being a retrofocus lens (which makes things a bit worse) your effective aperture is
(10 +1 ) x 2.8 =~f/31
if you have to close the aperture a couple of stops to make the lens do its best, you're at f/62 which means the smallest resolvable dot would cover an awful lot of pixels.

A 10x, NA 0.25 objective, would be effective
10/(2 x NA) = f/20 which is hugely better
We don't see them much in the UK, but I see many at <$50 in the US, so someone will have tried them.

At lower magnifications the math is less against you, but I'd still expect a noticeable difference.
_________________
Chris R
Back to top
View user's profile Send private message
tevans9129



Joined: 30 Nov 2017
Posts: 12
Location: TN

PostPosted: Mon Dec 04, 2017 4:14 pm    Post subject: Reply with quote

ChrisR wrote:
No answer...

My answer, "I don't know" Very Happy

But it should be better. At 10x, even at full aperture, you're very much affected by diffraction. Not accounting for it being a retrofocus lens (which makes things a bit worse) your effective aperture is
(10 +1 ) x 2.8 =~f/31
if you have to close the aperture a couple of stops to make the lens do its best, you're at f/62 which means the smallest resolvable dot would cover an awful lot of pixels.

A 10x, NA 0.25 objective, would be effective
10/(2 x NA) = f/20 which is hugely better
We don't see them much in the UK, but I see many at <$50 in the US, so someone will have tried them.

At lower magnifications the math is less against you, but I'd still expect a noticeable difference.


I very much appreciate your response CR. Being totally ignorant about microscope objective lens, it is confusing to me as to what components I would need to connect one to my bellows. Any suggestions for what would be needed for the connection? I have been reading on the subject but unfortunately, I am a slow learner. Sad
Back to top
View user's profile Send private message
tevans9129



Joined: 30 Nov 2017
Posts: 12
Location: TN

PostPosted: Mon Dec 04, 2017 4:22 pm    Post subject: Reply with quote

I have been looking at the objectives at the link below for a starting point using microscope objectives lens. Is this a reasonable path or should I look at something different? If, these are OK, what components will I need to connect to a Nikon PB-6 bellows? Thanks.

https://www.amazon.com/AmScope-4X-100X-Four-Achromatic-Objective/dp/B01G5W0UH4/ref=pd_rhf_se_p_img_5?_encoding=UTF8&psc=1&refRID=BFABDP0KJ1C6SFKV00JN


Last edited by tevans9129 on Mon Dec 04, 2017 4:45 pm; edited 1 time in total
Back to top
View user's profile Send private message
mawyatt



Joined: 22 Aug 2013
Posts: 983

PostPosted: Mon Dec 04, 2017 4:41 pm    Post subject: Reply with quote

This is a very inexpensive finite objective that works well around 4X.

http://www.amscope.com/accessories/objective/4x-plan-achromatic-compound-microscope-objective-lens-1.html

Originally found by Robert OToole.

https://www.closeuphotography.com/seventeen-dollar-plan-4x-objective/

https://www.closeuphotography.com/generic-objectives

You just need an RMS adapter and maybe an adapter for the PB6 bellows. To change magnification just change the bellows to adjust the lens to camera sensor distance, which is 160mm nominal for ~4X.

Another, but infinite object rather than finite objective, is the WeMacro 4X. This lens requires a tube lens of nominal 180mm for 4X, but works well with an old Nikon 200mm F4 "Q" (eBay for <$50) as a tube lens. This setup is a little more complex because of the extra "tube" lens, and changing magnification is more difficult because you much change the "tube" lens.

http://www.wemacro.com/?product=4x-infinity-plan-objective-lens


Best,

Mike
Back to top
View user's profile Send private message
Deanimator



Joined: 23 Oct 2012
Posts: 367
Location: Rocky River, Ohio, U.S.A.

PostPosted: Mon Dec 04, 2017 9:12 pm    Post subject: Reply with quote

mawyatt wrote:
This is a very inexpensive finite objective that works well around 4X.

http://www.amscope.com/accessories/objective/4x-plan-achromatic-compound-microscope-objective-lens-1.html

Originally found by Robert OToole.

https://www.closeuphotography.com/seventeen-dollar-plan-4x-objective/

https://www.closeuphotography.com/generic-objectives

You just need an RMS adapter and maybe an adapter for the PB6 bellows. To change magnification just change the bellows to adjust the lens to camera sensor distance, which is 160mm nominal for ~4X.

Let me heartily endorse this choice for a beginner on a budget.

I started using one a few weeks ago and have been extremely happy with it, especially for the investment required.

I've used mine both with tubes and with a bellows. I haven't settled on a method of killing reflection in the tubes, so I mostly use the bellows, which I think are a superior solution. I bought the tubes as a backup in case there were issues with the bellows.

I've got a 10x coming Wednesday. It was about twice as expensive as the 4x. It's cheap enough to take a chance on.
Back to top
View user's profile Send private message
Pau
Site Admin


Joined: 20 Jan 2010
Posts: 4003
Location: Valencia, Spain

PostPosted: Tue Dec 05, 2017 3:46 am    Post subject: Reply with quote

tevans9129 wrote:
I have been looking at the objectives at the link below for a starting point using microscope objectives lens. Is this a reasonable path or should I look at something different? If, these are OK, what components will I need to connect to a Nikon PB-6 bellows? Thanks.

https://www.amazon.com/AmScope-4X-100X-Four-Achromatic-Objective/dp/B01G5W0UH4/ref=pd_rhf_se_p_img_5?_encoding=UTF8&psc=1&refRID=BFABDP0KJ1C6SFKV00JN


Don't buy this set, they are entry level achromats intended for school grade microscopes (not bad for this application). The 40X and 100X oil wont have any utility for macro.
The 4X Plan referenced seems an excellent option.
_________________
Pau
Back to top
View user's profile Send private message
mawyatt



Joined: 22 Aug 2013
Posts: 983

PostPosted: Tue Dec 05, 2017 6:10 am    Post subject: Reply with quote

Deanimator wrote:
mawyatt wrote:
This is a very inexpensive finite objective that works well around 4X.

http://www.amscope.com/accessories/objective/4x-plan-achromatic-compound-microscope-objective-lens-1.html

Originally found by Robert OToole.

https://www.closeuphotography.com/seventeen-dollar-plan-4x-objective/

https://www.closeuphotography.com/generic-objectives

You just need an RMS adapter and maybe an adapter for the PB6 bellows. To change magnification just change the bellows to adjust the lens to camera sensor distance, which is 160mm nominal for ~4X.

Let me heartily endorse this choice for a beginner on a budget.

I started using one a few weeks ago and have been extremely happy with it, especially for the investment required.

I've used mine both with tubes and with a bellows. I haven't settled on a method of killing reflection in the tubes, so I mostly use the bellows, which I think are a superior solution. I bought the tubes as a backup in case there were issues with the bellows.

I've got a 10x coming Wednesday. It was about twice as expensive as the 4x. It's cheap enough to take a chance on.


Let us know how the AmScope 10X behaves, I suspect it's not going to be the jewel the 4X is....but we might get lucky again Very Happy

On APC/DX sensors you can just roll up a tube of Protostar or 1898 Beetle Black card stock to help squash internal reflections in the M42mm extension tubes. This might not work on full frame sensors, which is why I went with M52mm tubes long ago with more interior diameter to work with for flocking without interfering with the optical path. Evidently these 52mm tubes are difficult to find, and expensive on eBay. I've used these (See below for Nikon) in place of the 52mm tubes with the appropriate adapters. They are about 60mm diameter and very easy to flock. Get a few extra sets to make up a really tight fitting extension tube set. I use these on my permanent extension setups like with the Raynox 150 & 250 tube lenses and for the PN105 extension.

https://www.ebay.com/itm/Macro-Extension-Tube-Ring-For-Nikon-D2-D3-D200-D300-D700-D600-D800-D90-D7100-D4/181010937421?hash=item2a2517b64d:g:PfwAAOxyP4dTdJoE
Best,

Mike
Back to top
View user's profile Send private message
tevans9129



Joined: 30 Nov 2017
Posts: 12
Location: TN

PostPosted: Tue Dec 05, 2017 6:44 am    Post subject: Reply with quote

Many thanks to all for the comments, they were very helpful...I have ordered the Amscope 4x and 10x to begin with. Ted

Last edited by tevans9129 on Tue Dec 05, 2017 1:19 pm; edited 1 time in total
Back to top
View user's profile Send private message
Deanimator



Joined: 23 Oct 2012
Posts: 367
Location: Rocky River, Ohio, U.S.A.

PostPosted: Tue Dec 05, 2017 12:59 pm    Post subject: Reply with quote

mawyatt wrote:
Let us know how the AmScope 10X behaves, I suspect it's not going to be the jewel the 4X is....but we might get lucky again Very Happy

I figured for as cheap as it was, it was worth a try.

mawyatt wrote:
On APC/DX sensors you can just roll up a tube of Protostar or 1898 Beetle Black card stock to help squash internal reflections in the M42mm extension tubes. This might not work on full frame sensors, which is why I went with M52mm tubes long ago with more interior diameter to work with for flocking without interfering with the optical path. Evidently these 52mm tubes are difficult to find, and expensive on eBay. I've used these (See below for Nikon) in place of the 52mm tubes with the appropriate adapters. They are about 60mm diameter and very easy to flock. Get a few extra sets to make up a really tight fitting extension tube set. I use these on my permanent extension setups like with the Raynox 150 & 250 tube lenses and for the PN105 extension.

https://www.ebay.com/itm/Macro-Extension-Tube-Ring-For-Nikon-D2-D3-D200-D300-D700-D600-D800-D90-D7100-D4/181010937421?hash=item2a2517b64d:g:PfwAAOxyP4dTdJoE
Best,

Mike

I've got some flat black spray paint which I used when making a lens hood for my 500mm mirror lenses. I may give that a try.

I've got a very similar set of manual extension tubes which I bought when I was first getting started in macro. They worked, albeit with the expected limitations. I later bought a set of automated tubes, which were a good combination with my Tokina 100mm macro lens. Lately, I've combined the two sets of tubes with my Minolta 50mm manual reversed onto them. I got quite respectable results at a about 3.5x.
Back to top
View user's profile Send private message
mawyatt



Joined: 22 Aug 2013
Posts: 983

PostPosted: Tue Dec 05, 2017 1:35 pm    Post subject: Reply with quote

Long ago I tried the flat black spray paint, couple types, and results were not as good as flocking material like Protostar. With the flat paint you could easily see a reflection inside a long tube set when looking at an off-angle bright source. The reflection was much less noticeable with Protostar and the Beetle Black card stock is even better, almost no reflection at any angle. Think someone (Charles, Rik or Lou maybe) did a simple test awhile back and showed the Protostar and Beetle Black results.
Back to top
View user's profile Send private message
mawyatt



Joined: 22 Aug 2013
Posts: 983

PostPosted: Tue Dec 05, 2017 1:40 pm    Post subject: Reply with quote

tevans9129 wrote:
Many thanks to all for the comments, they were very helpful...I have ordered the Amscope 4x and 10x to begin with. Ted


Ted,

Let us know how the AmScope 10X works out, the 4X is quite good (I know I've had one since Robert posted about it, and did some chip images with it)...probably the best value for the $ around for an objective.

Best,

Mike
Back to top
View user's profile Send private message
Deanimator



Joined: 23 Oct 2012
Posts: 367
Location: Rocky River, Ohio, U.S.A.

PostPosted: Wed Dec 06, 2017 3:36 pm    Post subject: Reply with quote

mawyatt wrote:
Let us know how the AmScope 10X behaves, I suspect it's not going to be the jewel the 4X is....but we might get lucky again Very Happy

I just got my Amscope 10x and it looks very promising.

I haven't even taken an image with it, but through live view, it looks pretty good.

At max extension on the bellows, you can just squeeze 1/16" on a ruler into frame.

I have to get ready for work, but in between, I'm going to try to photograph something with good texture.

For what I paid for it, it seems like a good value.


Last edited by Deanimator on Wed Dec 06, 2017 5:35 pm; edited 1 time in total
Back to top
View user's profile Send private message
Deanimator



Joined: 23 Oct 2012
Posts: 367
Location: Rocky River, Ohio, U.S.A.

PostPosted: Wed Dec 06, 2017 5:33 pm    Post subject: Reply with quote

I did a stack with the 10x this evening.

The objective seems more than good enough.

The stack however was unusable because the step size was too big.

I'll do some more stacks tomorrow at a smaller step size.
Back to top
View user's profile Send private message
ChrisR
Site Admin


Joined: 14 Mar 2009
Posts: 7255
Location: Near London, UK

PostPosted: Wed Dec 06, 2017 6:01 pm    Post subject: Reply with quote

The smallest steps you might need with a 10x NA0.25, an APS sensor and 24MP, would be about 7 microns.
_________________
Chris R
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 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