I am new to this forum and would love to explore Componon 28mm f/4 after seeing RobertOToole's website. Would it be a possible to stack with RF 100mm macro lens? I understand I will need a coupling ring. Would I need anything else? My current setup is EOS R with RF 100mm f/2.8L and Laowa 25mm 2.5-5...

I've been searching for links on this topic for an article on my website, and this is a very good source:

How to decide outresolving?

viewtopic.php?p=236522

Take a look, lots of good material!

How does one calculate what the effective resolution of a lens is (in megapixels)? In other words: when does it no longer make sense to add more pixels? How does the resolving power (in micrometers) correlate to the sensor resolution that can resolve that power? For example, the Mitutoyo HR 10x NA ...

Scarodactyl wrote: ↑

Sun Feb 18, 2024 10:34 pm

I have a spare motic, but it's not quite as good as my last motic or my mitutoyo 10x with a touch of visible axial ca.

Thanks for the offer but I think I'll wait for another copy, which will be a little bit of a gamble to get good IQ, I'll post a request at some point.

I'm really glad Robert offered to help! I test objectives fairly often for forum members, but will be traveling soon, and would find it ticklish to get someone else's objectives tested and out the door in time. Your objectives will be in excellent hands with Robert. :D --Chris S. I'm glad to help. ...

Some US seller got his hands on few objectives (2x, 5x, 10x, 20x 80x) and I bought 2 of them - the 5x and 10x... According him they are in great condition, but I saw some posts in this forum of underperforms... I would like to test them and if necessary - use the 14 days return window. Unfortunatel...

Of-course good general sharpness of a lens benefit when using HR pixelshift mode. But do realise that the most benefit of using HR pixelshift mode, is a matter of "getting away" by the negative impact from interpolation algorithm for de-mosaicking the RGB Bayer pattern. Getting a much more “clean” ...

Pretty sure all Canon and Nikon AF systems stop down a bit to f/8 or so to AF and don't focus wide open. I tested just now, shining a flashlight down the barrel to watch the innards of Canon EF Macro 100mm f/2.8 L IS USM mounted on Canon R7 body with EF-EOS R adapter, manual mode set on f/11. It au...

Adding to Chris's excellent information... Lenses at 1:1 often have some uncorrected spherical aberration that causes focus to shift when the lens is stopped down. If you focus with aperture open, this can affect manual focusing as well as automatic. --Rik Just a note or two, Nikon's AF-fine tune a...

Hello Robert, Wauw, you wrote very comprehensive and detailed answers. I do appreciate very much. Thank you. - Glad I could help. One common mistake people make, and I find the fact to be to my advantage quite often is they write off older lenses due to a spec like the designed resolution being too...

Just checked 1:2 is in the optimized "range" of the 4/105 APO-Rodagon but in my experience since its designed for 1:6, the results aren't going to be pretty at all.
The APO-Rodagon D 120 which I am told is a re-labled Rodenstock APO Macro Sironar, should be much better at 1:2.

Robert

Hallo Robert, I have read your tests as for Laowa 100mm and Sigma 105mm Art with great interest. As all of your tests. By the clear and precise test procedures. (Like using a chip Wafer to have a full flat high detailed subject). Thank you. I appreciate that, I am always glad to hear feedback, posi...

When experimenting with reverse lens macro (on bellows) can something be gained by getting electrical contact with the reversed lens to control aperture? I'm using Canon EF 50/1.8 and 50/1.4 on a R6 to start with. Ideas and materials for a solution is there but is it worth the effort? In theory yes...

It really depends on the lens, there is no "golden rule" when it comes to special applications. Some macro lenses are great at 1x, others only mediocre or perhaps even bad - regardless of the aperture. Others start off really bad but get better once stopped down. A few precious (and expensive) ones...

(...)I did notice they finally went to a lead-screw focus rack (CASTEL-M) at least, after decades of rack and pinion drive(...) . by Robert Sorry for the technical ignorance but why is one system better than the other? Thanks. Hi Cunha, Rack in pinion drive is only safe horizontally. Any tilt verti...