www.photomacrography.net :: View topic - just starting out in insect macro with ok results, but....
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 
just starting out in insect macro with ok results, but....
Goto page Previous  1, 2, 3, 4, 5, 6
 
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Beginners Macro
View previous topic :: View next topic  
Author Message
ctron



Joined: 28 Jan 2016
Posts: 186

PostPosted: Thu Feb 11, 2016 2:38 pm    Post subject: Reply with quote

Higher mag, 4:1 on the centipede this time. Flashes still used as mentioned above. No major difficulties. I continue to like the detail I'm seeing. Perhaps I should have placed the ant on a white background.

Side note: The Janjso lights arrived today. I am impressed. They can be brought in really tight!

20 stacked images here.

Back to top
View user's profile Send private message
NikonUser



Joined: 04 Sep 2008
Posts: 2539
Location: southern New Brunswick, Canada

PostPosted: Fri Feb 12, 2016 6:57 am    Post subject: Reply with quote

The bristles are nice and sharp on the centipede.
More detail and more interesting would be a ventral view of the head and poison fangs.
_________________
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives
Back to top
View user's profile Send private message
ctron



Joined: 28 Jan 2016
Posts: 186

PostPosted: Sat Feb 13, 2016 7:41 am    Post subject: Reply with quote

Thanks, NikonUser. At some point soon, I hope to oblige.

Can someone tell me the diameter of the bottom threads of the Nikon 70100 objective? I'm going to attempt to drill a hole in the plastic cover of an old lens cap I have and then use an o-ring to hold the objective in place. Thanks in advance.
Back to top
View user's profile Send private message
ChrisR
Site Admin


Joined: 14 Mar 2009
Posts: 7789
Location: Near London, UK

PostPosted: Sat Feb 13, 2016 11:10 am    Post subject: Reply with quote

10x Nikon BE MRN70100
10x Nikon CFI E MRP70100.

Which?
The BE is rms so 0.8 inches.
The CFI I guess is 25mm.
_________________
Chris R
Back to top
View user's profile Send private message
ctron



Joined: 28 Jan 2016
Posts: 186

PostPosted: Sat Feb 13, 2016 12:17 pm    Post subject: Reply with quote

Ah oh, I didn't realize there was more than one part number until you mentioned it, Chris. Unfortunately, that means that all of the adapters I ordered this week won't work as it apparently isn't RMS (I obviously have the CFI). I knew something wasn't right when I took one of my old lens caps and tried drilling out a 13/16" hole and it was too small.

Now, the new question becomes: is this one worth keeping over the BE and, if not, is there a source for the BE as it doesn't appear that SEO has it?

On a side note, I did manage to drill a 25mm+ hole in the one lens cap and mount this CFI in it. I mounted it onto the front of my Zeiss Jenna 135mm f/3.5 lens, but, so far, the results are not very good. DOF is WAY smaller than anything else I've used and even my motorized homemade rail is too coarse! Maybe wrong objective and I should have the BE instead?
Back to top
View user's profile Send private message
rjlittlefield
Site Admin


Joined: 01 Aug 2006
Posts: 19183
Location: Richland, Washington State, USA

PostPosted: Sat Feb 13, 2016 12:48 pm    Post subject: Reply with quote

I guess it's a little late to make this point, but trying to use shortened names for objectives is an invitation to confusion. "CFI" is just Nikon's designation for "chrome-free infinity", meaning objectives that are designed for use with a tube lens and are fully corrected for lateral chromatic aberration in the objective. "BE" is Nikon's designation for a particular line of objectives that have 45 mm parfocal distance and an RMS thread. The MRN70100 is both CFI and BE, which is why I described it earlier in this thread as "Nikon CFI BE, part number MRN70100".

Quote:
is there a source for the BE as it doesn't appear that SEO has it?

The last time I asked SEO what objectives they carried, their reply included the MRN70100, even though at that time the MRN70100 did not appear on their website. If you want the MRN70100, I suggest sending them email to ask about it.

Quote:
DOF is WAY smaller than anything else I've used and even my motorized homemade rail is too coarse! Maybe wrong objective and I should have the BE instead?

All 10X NA 0.25 objectives will have the same DOF. The MRP70100 has a tiny bit more working distance than the MRN70100, spec'd at 7.0 mm WD versus 6.7 mm. In my tests on image quality, it seems that the MRP70100 is a little more vulnerable to vignetting. It may also be a little more vulnerable to veiling glare, but that was a casual observation that I did not specifically test for. For these reasons, plus its slightly higher price, I do not recommend the MRP70100 if the MRN70100 is available. However, if I had the MRP70100 in hand, I don't think I would find it worth the trouble to exchange.

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



Joined: 28 Jan 2016
Posts: 186

PostPosted: Sat Feb 13, 2016 1:01 pm    Post subject: Reply with quote

Thanks, Rik. I emailed them and will see what they say. The problem is that all of the adapters I have coming use RMS, but I could live with that if I had to.

How do you recommend focusing with these objectives? Even when I have my motor on slow speed, it's still moving too much and so the stacks end up with all sorts of out of focus areas. My system is too coarse to go backwards to try and correct too. Thanks.

DOF seems the narrowest I've ever encountered and this is at 5x. I have the objective mounted onto the Zeiss Sonnar 135mm f/3.5 with the lens set at infinity. I am able to focus, but the area in focus is so tiny that it seems impossible to move the motor correctly to the next area. This can't be normal!?!. Is it possible to increase DOF for these objectives? Maybe something else I'm overlooking? I'm pretty sure some of the images I've seen were hand focused, so something's not right.
Back to top
View user's profile Send private message
rjlittlefield
Site Admin


Joined: 01 Aug 2006
Posts: 19183
Location: Richland, Washington State, USA

PostPosted: Sat Feb 13, 2016 2:21 pm    Post subject: Reply with quote

Quote:
DOF seems the narrowest I've ever encountered and this is at 5x. ... This can't be normal!?!.

I hate to be the bearer of bad news, but shallow DOF is completely normal. The laws of physics regarding diffraction are quite strict. That's why we use focus stacking: to work around them.

Using standard criteria, the optical DOF of any objective at NA 0.25 is 0.0088 mm. Pushing the objective below 10X by using a short rear lens does not change DOF unless you get so low that the captured image is limited by sensor resolution rather than lens resolution.

Quote:
Is it possible to increase DOF for these objectives?

Sure, you can add an iris or even a fixed stop just behind the objective. However, stopping down to increase DOF will result in reduced resolution due to diffraction. That's just the way light works. Given that you're running at 6.75X (using a 135 mm rear lens), with an NA 0.25 objective, your effective f-number right now is f/13.5. If you're willing to live with f/27, then you could add a stop with diameter 5 mm and increase your DOF to 0.035 mm. (Optical DOF varies inversely with NA^2.)

Quote:
I'm pretty sure some of the images I've seen were hand focused, so something's not right.

Stacking by hand versus using a motor does not imply using larger or sloppier focus steps. Hand focused 10X stacks are just done using a fine screw rail or a microscope focus block, combined with a good measure of patience. See the collection of setups linked at http://www.photomacrography.net/forum/viewtopic.php?p=55311#55311 for a wide variety of ways to make the movements.

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



Joined: 28 Jan 2016
Posts: 186

PostPosted: Sat Feb 13, 2016 3:45 pm    Post subject: Reply with quote

[quote="rjlittlefield"]
Quote:

Sure, you can add an iris or even a fixed stop just behind the objective.


What about a small washer affixed to the front of the microscope objective, slightly smaller than the opening?

Quote:

Stacking by hand versus using a motor does not imply using larger or sloppier focus steps. Hand focused 10X stacks are just done using a fine screw rail or a microscope focus block, combined with a good measure of patience. See the collection of setups linked at http://www.photomacrography.net/forum/viewtopic.php?p=55311#55311 for a wide variety of ways to make the movements.


Thanks. One of the links you mentioned lead me to this one:

http://www.photomacrography.net/forum/viewtopic.php?t=10821

Is a microscope stage fine enough for the job? There, he has an infinity objective on telephoto so I assume it can, and then just carefully hand turned. Before I start looking in that direction, I may be able to modify the circuitry of my coarse rail for slower speed, which might get me closer. Just FYI, I use these:

https://jet.com/product/detail/feb465b489054ae89d32afdb53c765c0?jcmp=pla:ggl:cameras_optics_a3:camera_optic_accessories_camera_parts_accessories_a3_other:na:na:na:na:na:2&code=PLA15&k_clickid=15d3103b-e6a8-4a8d-a6b8-4b257c357ec2&abkId=403-506151&gclid=CMXmwqfm9coCFYdbhgod384OdA

...except a hole was drilled into the focusing shaft and a direct drive motor used in series with the shaft. The motor controller has two speeds (fast or slow) and is not very precise. I may be able to change the speed to something slower, not certain.

I must say that this took me by surprise. I didn't realize that DOF would be so small with these objectives and I may have to forego on higher mags and stick with the reversed lens at 4:1 and under. My budget is very limited. No room for commercial rails unless I can make mine or a cheap microscope stage work.
Back to top
View user's profile Send private message
ctron



Joined: 28 Jan 2016
Posts: 186

PostPosted: Sat Feb 13, 2016 7:09 pm    Post subject: Reply with quote

Just a quick update: I was able to find a modification to slow down the focus motor and, this time, I was able to complete a fair (not perfect) stack. However, I have yet to surpass the sharpness of my reverse kit lens... in fact the kit lens was still sharper at this level. Thoughts?
Back to top
View user's profile Send private message
rjlittlefield
Site Admin


Joined: 01 Aug 2006
Posts: 19183
Location: Richland, Washington State, USA

PostPosted: Sat Feb 13, 2016 7:55 pm    Post subject: Reply with quote

ctron wrote:
However, I have yet to surpass the sharpness of my reverse kit lens... in fact the kit lens was still sharper at this level. Thoughts?

If the image through the objective is not much sharper than your reversed kit lens, then the most likely problem is motion blur. The only other possibilities I can think of are that the objective is seriously out of whack (not likely for a new objective) or your setup has dragged it way off its design point.

Tell us again what optics and illumination you're using?

Quote:
What about a small washer affixed to the front of the microscope objective, slightly smaller than the opening?

That would work, especially at image center, but black paper would be better. With a washer, you're likely to get lots of veiling glare due to reflections off the sides of the hole.

The stop is usually placed behind the objective because in that position its effects are more likely to be uniform across the frame.

Quote:
Is a microscope stage fine enough for the job?

Yes. The only concern is to be sure that the fine focus knob has enough travel to cover the total depth you care about. Good blocks can travel their entire distance, typically about 1 inch, under control of the fine focus knob. Not-so-good blocks can only move much less than that. One of my scopes has a fine focus range of only about 0.3 mm. That one would not be much use for stacking.

Quote:
I must say that this took me by surprise. I didn't realize that DOF would be so small with these objectives

Right, there's a lot of information and it's hard to absorb it all. That said, I can't resist quoting a bit from earlier in this same thread: The DOF will be approximately 0.01 mm ...

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



Joined: 28 Jan 2016
Posts: 186

PostPosted: Sat Feb 13, 2016 9:33 pm    Post subject: Reply with quote

Rik,

How about the "old" issue, lighting! Apparently, for the first stack, I had a combination of insufficient fineness and illumination. This time, after the now finer focus control and increasing the exposure resulted in the attached image. Now that one is getting much closer. The details on the body and head were not visible in the reversed lens set up at the same mag. The reason there's still blurriness is because now I'm having issues with my focus motor stalling since I slowed it down and it's something I'll have to work on but at least I'm proceeding in much smaller focus steps. Note that it's tough to manipulate these tiny house ants into position and it has been hit and miss, can't just stick a pin in them. One breath and they're gone too!

Back to top
View user's profile Send private message
ctron



Joined: 28 Jan 2016
Posts: 186

PostPosted: Sun Feb 14, 2016 4:59 pm    Post subject: Reply with quote

I think I finally have this figured out. The reason for the softness was not using flash... the attached image is with the Ikea lights. Once I switched to flash, significantly sharper and I'm not getting the flaring nor lack of contrast as with the reversed lens. Only issue remaining to work out is focus steps. I may be able to do something with my crude rail, but the modification I made to slow down the motor causes too much power loss and the system stalls. Until I work around it, I'm going to try a 5mm washer behind the objective tomorrow as Rik suggested.

This image is about 100 frames, stacked in Zerene. Had to do a lot of post processing to get the dust streaks out of it. I would have posted one of the latest ones illuminated by flash, but looks strange with rings of sharpness and then blur so will do so after modifications.

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 -> Beginners Macro All times are GMT - 7 Hours
Goto page Previous  1, 2, 3, 4, 5, 6
Page 6 of 6

 
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