sharpest lens for shooting small/large artwork

[Monetbeck00]

What is the sharpest prime autofocus Canon lens for shooting artwork ranging in size from 8x10" to 40x60"?

UPDATED w info requested in replies (thank you, guys)...

I need super-sharp photos of my paintings, which range in size from 8x10" to 40x40". I am shooting with my EOS RP. I can shoot by available light outdoors (not in direct sunlight) or with my Elinchrome strobes. Indoors, I have about 10- 15' to move back from the artwork. Someone recommended the Canon 180mm EF Macro (Ken Rockwell says it's the sharpest Canon macro lens). My budget is up to $600, and I don't mind a used or refurbished lens. I do need autofocus due to lousy eyes. I am also wondering if a macro lens will work for large artwork. 

Thanks for your feedback!

[Tronhard]

Your question begs a few questions:

1. The most fundamental question is what is your budget?  We can suggest highly expensive glass you can't afford
2. How much space do you have between your camera and the 40"x60" subjects?  Long focal length lenses (good for eliminating distortion) will need to take a step back for such a large subject.

Rockwell's comment was made in 2022, but conventional wisdom suggests you should use RF glass on a an R body and optics have come a long way. The size of the space available may dictate a different focal length, 180mm will need a very large studio space, but the RF100 Macro lens might well fit the bill for you, and you can get one from Canon's Refurbished site - for a reasonable price.
Shop Canon Refurbished EF 100mm f/2.8L Macro IS USM | Canon U.S.A., In

You will want to not be at the lowest possible f/stop, something in the f/4 - f/5.6 to guarantee a deep depth of field and of course on a tripod, using a remote to avoid your finger moving the camera, with electronic shutter to avoid shutter shock.

[kvbarkley]

Macros are good because they are generally designed for flat fields of focus, that is that the focus is the same across the whole sensor.

What you might not want is a 180mm lens. The fov on a FF camera is 11.5 degrees in the long dimension.

you have a right triangle consisting of half the fov to half of the artwork, or that the distance will be:

30/fd = tan(fov/2) which turns out to be 300 inches or 25 ft. If you have this much room, the 180mm lens is a good choice.

100mm would be 170" away or about 14 feet.

[Monetbeck00]

A BIG thanks for the quick replies! I am glad I asked, as I don't have the 25' to back away from a large painting! I will take a look at that EF 100mm f/2.8L Macro IS USM.

[Tronhard]

How much space do you have?  You can get excellent non-macro lenses of a shorter focal length, such as the RF 85mm lens.  If this is a professional application, it might be worth renting any lens you want to consider buying.

BTW, I love Monet too! 

[Monetbeck00]

I've got about 12c18' feet, and realistically, about 10'x16' floor space for stands and an easel. Unless, of course, I shoot the copy of my paintings outdoors. The 100mm should work in my tight space. I also like kvbarkley's tip about a gridded background for ensuring a distortion-free setup. 

Yeah, Monet's work is amazing. Long have admired his sense of color. I love your Tolstoy quote!

[kvbarkley]

I should point out that with today's distortion corrections, having a perfect lens is not that necessary. In fact, if you use a gridded background and make sure that some of it shows all around the artwork, you can easily tell if you have distortion that needs correcting, and verify that you have corrected it correctly. 8^)

[kvbarkley]

You can adapt this test to evaluate whatever you end up with:

https://bobatkins.com/photography/technical/lens_sharpness.html

[Monetbeck00]

Thanks, kvbarkley, for the bobatkins link. Great, simple, practical tips on ensuring the best setup. Love his t-square method for making sure the camera is square and centered to the artwork. 🙂

[Waddizzle]

“ UPDATED w info requested in replies (thank you, guys).. “

Please don’t do that. It breaks the continuity of the discussion. Totally destroys it.