Can I push the resolution of a 1:1 macro lens?

Have questions about the equipment used for macro- or micro- photography? Post those questions in this forum.

Moderators: Pau, rjlittlefield, ChrisR, Chris S.

Ichthyophthirius
Posts: 1100
Joined: Thu Mar 07, 2013 5:24 am

Can I push the resolution of a 1:1 macro lens?

Post by Ichthyophthirius »

Hi,

I have a 150mm f/2.8 macro lens (Sigma APO EX DG IF HSM; last version before the OS). For insects, I would use it at f/8 and at its closest focus distance (1:1).

My questions: Would I be able to see a little more detail resolved if I

a) Pushed this lens past 1:1 with extension tubes or a teleconverter? How quickly would I reach empty magnification?
b) Chose a camera with a smaller pixel pitch? How many megapixels would I need on a FF sensor to make full use of (the center of) the lens?

Cheers, Ichty

rjlittlefield
Site Admin
Posts: 21137
Joined: Tue Aug 01, 2006 8:34 am
Location: Richland, Washington State, USA
Contact:

Re: Can I push the resolution of a 1:1 macro lens?

Post by rjlittlefield »

A lot depends on what "f/8" means.

If it means a Canon-style f/8 that becomes effective f/16 at 1:1, then the calculations come out to about 45 megapixels on FF, using the common guideline of 2 pixels per cycle at diffraction cutoff for lambda 550 nm.

But if it means a Nikon-style f/8 that means effective f/8 regardless of magnification, then the same calculation comes out to about 179 megapixels.

These calculations are just guidelines, of course, but I think the message is clear: effective f/16 is close to the diffraction limit on modern FF sensors, while effective f/8 is far from it.

What camera do you have now? Have you run an aperture series to see how far you can stop down before you start losing detail from diffraction?

--Rik

Ichthyophthirius
Posts: 1100
Joined: Thu Mar 07, 2013 5:24 am

Re: Can I push the resolution of a 1:1 macro lens?

Post by Ichthyophthirius »

Hi Rik,

I'm using a Canon 500D (APS-C; 15 MP; 4.68 µm pixel pitch).

I haven't done an aperture series yet.

I have tried out the EF 40mm f/2.8 for macro recently. I noticed that when I pushed it towards 1:1 (forward with extensions) and then even further towards 1.5:1 (reversed with extensions), I would still get more and more detail. That made me wonder if I could get more detail with the Sigma 150mm as well by using a teleconverter or getting a new camera with higher pixel density (don't have either so I better ask here if it's worth the expense) :D

Cheers, Ichty

rjlittlefield
Site Admin
Posts: 21137
Joined: Tue Aug 01, 2006 8:34 am
Location: Richland, Washington State, USA
Contact:

Re: Can I push the resolution of a 1:1 macro lens?

Post by rjlittlefield »

Ichthyophthirius wrote:
Wed Sep 23, 2020 6:02 pm
wonder if I could get more detail with the Sigma 150mm as well by using a teleconverter or getting a new camera with higher pixel density
I expect the answer to that question is definitely "yes", but you may need to open a bit wider to reduce diffraction.

See http://www.photomacrography.net/forum/v ... hp?t=21751 , and note that in that study the resolution target was at long distance so effective f/16 is very close to nominal f/16. In the f/16 column, second from right, there is close to no improvement in visible detail from adding the teleconverter. But in the f/11 column, adding the teleconverter resolves a couple more sets of bars. That study was done using same camera as yours, Canon T1i = 500D. The lens was different, but also high end.

--Rik

joshmacro
Posts: 17
Joined: Thu Apr 23, 2020 5:25 pm
Location: New York

Re: Can I push the resolution of a 1:1 macro lens?

Post by joshmacro »

Hi Itchy. Have similar history to where you are at. Instead of considering a FF sensor with more megapixels you can also consider a smaller sensor. I used my Nikon D750 with the Sigma 150 macro for many years and still do. But I also got an Olympus OM-D E-M5 with the Oly 60mm Macro lens (all used so not that much money). I also bought the Kenko 26mm auto extension tubes. So right now I can get a max 1.43 magnification on the Oly set-up, so an object of 12mm x 9mm will fill up my MFT sensor compared to 36mm x 24mm on my FF sensor with 1:1 magnification. The huge benefit of the my setup is that you can tether the Oly and the Kenko tubes are auto so I can focus stack with my laptop instead of having to buy a rail, etc. In terms of image quality the Oly and 60 macro and very sharp. The dynamic range is not comparable to the D750 and that's really the drawback to MFT, but I don't find it to be a major issue. However, I always use a flash so the saturated image I get seems to make up for the lack of dynamic range. Hope this gives you another option to consider.

clarnibass
Posts: 109
Joined: Fri Jun 10, 2016 11:33 pm

Re: Can I push the resolution of a 1:1 macro lens?

Post by clarnibass »

I've never tried a teleconverter, though I've heard that (with a good one) it's probably better than extension tubes...

I have used extension tubes for a few years until I changed setup. Mostly a 105mm x1 lens with 27.5mm tube and/or a 52.5mm tube. I found "weird" results some times, so I asked about it here, and what I was told is that macro lenses often have correcting elements, that still correct for x1 when the lens is magnified beyond that.

When I was using the 105mm lens with 23.5mm extension, I got better resolution than without, absolutely enough to use it.
With the 52.5mm extension, results were borderline better, with some loss of contrast. When viewed/printed at the same size, hard to say if there was much of a difference.
When adding the total of 80mm extension, there was a minor loss of sharpness and a very significant loss of contrast.
I basically stopped using the 80mm extension, and mostly stopped using the 52.5mm extension too.
I then changed to a coupled reversed lens setup that had about the same magnification as the 105mm + 80mm extension setup and results were much better, no comparison.
Last edited by clarnibass on Fri Sep 25, 2020 2:54 am, edited 1 time in total.

Lou Jost
Posts: 4644
Joined: Fri Sep 04, 2015 7:03 am
Location: Ecuador
Contact:

Re: Can I push the resolution of a 1:1 macro lens?

Post by Lou Jost »

Modern close-focusing lenses move their elements internally at different rates as you refocus, to optimize the optics for the chosen magnification and sensor distance. Using extension tubes moves the lens away from that optimum, so a good teleconverter (which magnifies the optimized image) should be better than extension tubes, for those kinds of lenses. Teleconverters are also better than extencion tubes for lenses that are tightly optimized for a given magnification, for example the 105mm Printing Nikkor, since extension tubes move them away from that optimum.

Reversed modern lenses with floating elements that are going to be used to acieve magnification m should be set to be focused at 1/m and then reversed, again to maintain the optimum position for the floating elements.

Coupled lenses theoretically should be better than lenses on extension, but it does depend on finding good combinations. Robert O'Toole's test posts here and on his website gives much valuable information about that:
www.closeuphotography.com

JKT
Posts: 186
Joined: Fri Oct 28, 2011 9:29 am
Location: Finland
Contact:

Re: Can I push the resolution of a 1:1 macro lens?

Post by JKT »

Some years ago I tested extension tubes with Canon 100mm L macro and it seemed to me the extension tubes worked reasonable if the lens was set for minimum focus. Move away from that and things get bad fast. So in order to get different magnifications you'd need different amount of tubes.

Ichthyophthirius
Posts: 1100
Joined: Thu Mar 07, 2013 5:24 am

Re: Can I push the resolution of a 1:1 macro lens?

Post by Ichthyophthirius »

Thank you for sharing their experiences and suggestions! I think I will give the teleconverter a try while keeping a close eye on the apertures I use.

Thomas
Posts: 16
Joined: Fri Sep 27, 2019 5:11 pm

Re: Can I push the resolution of a 1:1 macro lens?

Post by Thomas »

Ichthyophthirius wrote:
Wed Sep 23, 2020 4:28 pm
My questions: Would I be able to see a little more detail resolved if I

a) Pushed this lens past 1:1 with extension tubes or a teleconverter? How quickly would I reach empty magnification?
b) Chose a camera with a smaller pixel pitch? How many megapixels would I need on a FF sensor to make full use of (the center of) the lens?
I use a Canon EOS RP (pixel pitch ~5.76µm) with a Sigma 150mm 1:2.8 APO EX DG HSM macro lens. Used directly, it delivers clean, sharp shots. I just bought a cheap 65mm extension tube from ebay to try out. First impressions from a few non-scientific test shots and stacks:
* I can get a little more detail from the extra magnification, but really have to work for it and compromise.
* Colour fringing.
* Edge and centre focus plane doesn't appear to be flat (?).
* Auto-focus doesn't lock on frequently even in well-lit scenarios.
* Camera (USB tethered to PC) froze repeatedly during stacking. Seems to have problems shifting the lens focus.
* Tethered remote focus fine-adjustment does not work well
* The plastic extension tubes bend with such a heavy lens. Maybe fine in studio setups, but I wouldn't take it for a walk.

Lou Jost
Posts: 4644
Joined: Fri Sep 04, 2015 7:03 am
Location: Ecuador
Contact:

Re: Can I push the resolution of a 1:1 macro lens?

Post by Lou Jost »

As I explained above, with modern lenses that have floating elements, you should have used a teleconverter instead of extension tubes. Otherwise you aremoving the lens far from ist design point.

Ichthyophthirius
Posts: 1100
Joined: Thu Mar 07, 2013 5:24 am

Re: Can I push the resolution of a 1:1 macro lens?

Post by Ichthyophthirius »

Thomas wrote:
Wed Oct 07, 2020 12:32 am
I use a Canon EOS RP (pixel pitch ~5.76µm) with a Sigma 150mm 1:2.8 APO EX DG HSM macro lens.

* Camera (USB tethered to PC) froze repeatedly during stacking. Seems to have problems shifting the lens focus.
Hi,

I think I will try Lou's suggestion with the teleconverter.

But I'm really interested in your experience with the EOS RP as that is the camera I'm considering. When you talk about stacking, can you use the RPs internal focus bracketing with the Sigma lens? That would amazing.

Regards, Ichty

Lou Jost
Posts: 4644
Joined: Fri Sep 04, 2015 7:03 am
Location: Ecuador
Contact:

Re: Can I push the resolution of a 1:1 macro lens?

Post by Lou Jost »

When you talk about stacking, can you use the RPs internal focus bracketing with the Sigma lens? That would amazing.
I found that the Sigma 70mm Art lens in L mount can automatically focus-stack with the Panasonic S1R. Don't know about other mounts....

Thomas
Posts: 16
Joined: Fri Sep 27, 2019 5:11 pm

Re: Can I push the resolution of a 1:1 macro lens?

Post by Thomas »

Ichthyophthirius wrote:
Thu Oct 08, 2020 6:12 am
But I'm really interested in your experience with the EOS RP as that is the camera I'm considering. When you talk about stacking, can you use the RPs internal focus bracketing with the Sigma lens? That would amazing.
I'm very happy with the RP.
* Stacking works just fine with the Sigma 150mm, as well as
* Sigma 150mm + Nikon CFI Plan Achromat 10x (MRL00102),
* and Sigma 150mm + Nikon CFI BE Plan Achromat 4x (MRN70040)

I use the built-in stacking feature outdoors, and USB tethered stacking with the Canon EOS software indoors.

It's embarrasingly easy compared to my pre-EOS RP setup. No more stepper motors etc. "Simply place on a slab of granite" :) , press the shutter, and it chugs away several shots per second.

lothman
Posts: 495
Joined: Sat Feb 14, 2009 7:00 am
Location: Stuttgart/Germany

Re: Can I push the resolution of a 1:1 macro lens?

Post by lothman »

Thomas wrote:
Sun Oct 11, 2020 2:33 am
* Sigma 150mm + Nikon CFI Plan Achromat 10x (MRL00102),
* and Sigma 150mm + Nikon CFI BE Plan Achromat 4x (MRN70040)
that's interesting, what is the max stack depth in mm you can achieve with the 150mm macro lens together with the 10x lens.

Post Reply Previous topicNext topic