Focussing problems with the RF 100mm macro lens.

XL+

EOS M6 Mark II
CR Pro
Sep 15, 2016
89
31
recently: The Tyrol, Austria
Hello!
I am dissatisfied by my RF 100mm macro lens. Primarily happy with the 1.4x magnification, it shows focussing problems when the aperture is changed and has to be refocussed by hand each time. like on "The digital picture" page described.
My question is, if someone has found an solution how to deal with it. It is annoying to refocus each time. I wrote to Canon, if there an existing firmware update. No answer was sent.
I do use an Novoflec macro slider to adjust the focus point.
 
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stevelee

FT-QL
CR Pro
Jul 6, 2017
2,216
921
Davidson, NC
Perhaps that is something that can be fixed. But for really close focusing it would not be a problem for me. I focus manually and decide the magnification first (by using the focusing ring, which is then left untouched). Then I use the rail to move the focus plane exactly where I want it, moving the rail each time if I plan to do stacking.

I don’t have that luxury of time when chasing flying insects. Sometimes I try autofocus, and sometimes I focus manually and move myself back and forth to focus. Luck seems to determine which works.
 

stevelee

FT-QL
CR Pro
Jul 6, 2017
2,216
921
Davidson, NC
I failed to mention that I use the EF 100mm macro on my DSLR, so am not contending with the breathing on the RF. I use tubes to get greater than 1:1 magnification.
 

neuroanatomist

I post too Much on Here!!
CR Pro
Jul 21, 2010
26,400
5,161
But for really close focusing it would not be a problem for me. I focus manually and decide the magnification first (by using the focusing ring, which is then left untouched). Then I use the rail to move the focus plane exactly where I want it, moving the rail each time if I plan to do stacking.

I failed to mention that I use the EF 100mm macro on my DSLR, so am not contending with the breathing on the RF. I use tubes to get greater than 1:1 magnification.

It might be a problem for you with the RF lens... The issue isn't focus breathing (which the EF 100L has in spades, at 1:1 it's framing at around 68mm), but rather focus shift (from which the EF version does not suffer). If you're shooting at a aperture narrower than wide open, after you manually set focus the focal plane will shift backward when you take the shot. At sufficiently narrower apertures, the DoF is deeper and can mask the effect of focus shift. If you're stacking, it's not an issue because the focus shift just adds a constant backfocus offset, but you'll be capturing focal planes all through your subject anyway (but you may want to start the stack a bit in front of the subject).
 
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stevelee

FT-QL
CR Pro
Jul 6, 2017
2,216
921
Davidson, NC
It might be a problem for you with the RF lens... The issue isn't focus breathing (which the EF 100L has in spades, at 1:1 it's framing at around 68mm), but rather focus shift (from which the EF version does not suffer). If you're shooting at a aperture narrower than wide open, after you manually set focus the focal plane will shift backward when you take the shot. At sufficiently narrower apertures, the DoF is deeper and can mask the effect of focus shift. If you're stacking, it's not an issue because the focus shift just adds a constant backfocus offset, but you'll be capturing focal planes all through your subject anyway (but you may want to start the stack a bit in front of the subject).
Thanks for the clarification. In the method I explained, breathing is not an issue because the lens is focused first to set the magnification, but, yes, I did misuse the term. I guess with the RF lens, I would use even more stacking.
 
Oct 2, 2021
3
4
I have used this RF lenses for a few months now and comparing it with the EF lens on a Canon R5. To be honest the RF lenses has a such severe back focusing problem that it is useless in macro photography. It is not better in portrait photography since if you focus on the eye the eye will be slightly out of focus. For those who say that they focus manually I would suggest to them that paying $2000 for a lens that can't autofocus is a useless waste of money. I would recommend a Laowa 100mm f/2.8 2X Ultra macro that has a much sharper image! The EF lenses is a much superior lenses for macro using autofocus. Taking a photo of an insect that is moving on a flower is much easier done with autofocus than with manual focus. Also if you focus on the stigma of a flower it will be out of focus with the RF lenses but perfect with the EF... And no it is not a bad copy of the lens.

If your interested in buying the RF lens do yourself a favor and do a review research on youtube before spending $2000. For example, look at Christopher Frost or Dustin Abbot reviews. They are polite but definitely don't recommend this lens. I don't know if a firmware upgrade can fix this problem but I will give Canon a few months to fix this. If nothing is done I will sell at rebate this useless macro lens. The EF lenses works just fine with my R5 and does beautiful pictures. The RF is really bad for serious macro photographers.
 
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neuroanatomist

I post too Much on Here!!
CR Pro
Jul 21, 2010
26,400
5,161
I have used this RF lenses for a few months now and comparing it with the EF lens on a Canon R5. To be honest the RF lenses has a such severe back focusing problem that it is useless in macro photography. It is not better in portrait photography since if you focus on the eye the eye will be slightly out of focus. For those who say that they focus manually I would suggest to them that paying $2000 for a lens that can't autofocus is a useless waste of money. I would recommend a Laowa 100mm f/2.8 2X Ultra macro that has a much sharper image! The EF lenses is a much superior lenses for macro using autofocus. Taking a photo of an insect that is moving on a flower is much easier done with autofocus than with manual focus. Also if you focus on the stigma of a flower it will be out of focus with the RF lenses but perfect with the EF... And no it is not a bad copy of the lens.

If your interested in buying the RF lens do yourself a favor and do a review research on youtube before spending $2000. For example, look at Christopher Frost or Dustin Abbot reviews. They are polite but definitely don't recommend this lens. I don't know if a firmware upgrade can fix this problem but I will give Canon a few months to fix this. If nothing is done I will sell at rebate this useless macro lens. The EF lenses works just fine with my R5 and does beautiful pictures. The RF is really bad for serious macro photographers.
Confirm that you don't experience the back focus with the lens at f/2.8. If you do, it is likely a malfunctioning lens. The focus shift that is part of the optical design occurs only when you stop down, and generally only at macro distances. Your reference to back focused portraits makes me wonder if you simply have a bad copy of the RF 100L Macro.
 
Oct 2, 2021
3
4
Confirm that you don't experience the back focus with the lens at f/2.8. If you do, it is likely a malfunctioning lens. The focus shift that is part of the optical design occurs only when you stop down, and generally only at macro distances. Your reference to back focused portraits makes me wonder if you simply have a bad copy of the RF 100L Macro.
I confirm that I don't experience focus shift at f/2.8. And for the portrait remark take a look at the Dustin Abbot review when he talks of the picture he took of his cat...I experienced the same problem of focus shift at f/5.6.