Bbarn Loc: Ohio

I recently acquired a Fotasy adapter that allows me to use some lenses from the 70s on my EOS RP. It fits and works well. Of course it meters in manual mode only and you have to focus, but it's fun to put a few older Minolta primes to use once again. Since it's all manual, it's nice to see the exposure in the mirrorless viewfinder before pulling the trigger.

MD 28 f2.8 Lens


MD 135 f2.8

CHG_CANON Loc: the Windy City

Consider using shutter priority, auto ISO and the EC at +0.7 (if shooting in RAW). I have a similar adapter for my old FD lenses on a Sony mirrorless. At first I tried manual exposure, but spent more time getting the exposure, anything with the ability to move, moved before I could even get to the focusing part. Someone gave me the tip on shutter priority and just let the camera manage the whole exposure so you can worry about focusing. Aperture priority works the same and the camera will try to keep the ISO around ISO-0100. But, since your EOS RP doesn't have IBIS, you might find shutter priority more useful to keep the shutter fast enough. Have fun!

Bbarn Loc: Ohio

It appears...

If the ISO is fixed, Auto exposure won't work in Shutter Priority since the camera has no control over aperture (or ISO). Auto exposure seems to work in all other program/priority modes even if ISO is fixed.

If ISO is set to AUTO, the automatic exposure will work in all the program/priority modes including Shutter Priority.

w00dy4012 Loc: Thalia, East Virginia

I've shot in manual with both Sony 7aii's and a 7aiii with no problems, usually using ISO 100. Just set the desired aperture on the lens, focus, and adjust shutter speed on on he camera until the desired exposure is showing in the viewfinder.

CHG_CANON Loc: the Windy City

That's my point: The camera can handle the exposure completely and you only have to worry about focus, not manual focus and manual exposure. For shutter priority and AUTO ISO, just set the speed and let the camera handle it from there. I'm not saying "you can't" or "shouldn't" for manual exposure. Rather, consider putting all your mental effort on the focus and let the camera handle the exposure.

By way of example, here the subject is moving and not waiting for me to get the exposure and then the focus:

Sand wasp and goldenrod by Paul Sager, on Flickr

w00dy4012 Loc: Thalia, East Virginia

Yes, you can do that too. I thought you were saying you were having a problem with manual. I like to go full manual because it lows me down and makes me think. Great image, by the way.

CHG_CANON Loc: the Windy City

My "problem" was only that my slow and deliberate development of the manual exposure had me missing too many shots. Although manual exposure is my typical EOS DSLR shooting style for all subjects, I couldn't seem to get as efficient when I started with the Sony mirrorless. Maybe now a few years later, it wouldn't seem as challenging. I was pushing myself for moving subjects then too where maybe the shutter priority config is a permanent change for me with these manual focus lenses.

Bike guy Loc: Atlanta

Those of you that have Canon FD lenses attached to Sony mirror less, what ones do you like or have? I have the 2.8 28 mm, and 135 mm SC, 3.5.

CHG_CANON Loc: the Windy City

I have used the 28 f/2.8, 35 f/2, 80-200 f/4L, and 135 f/2. All worked great. I mention them because I decided to not maintain parallel FD-Sony and EF-EOS systems. Otherwise, I'd still have them all, and sometimes, I wish I still did.

Bike guy Loc: Atlanta

Thanks

petrochemist Loc: UK

Personally I prefer aperture priority. No need for auto ISO but it can still be used if desired.
In Av the ISO will be whatever I set it at, on Auto it will use the cameras standard algorithm, keeping the ISO low if shutter speed allows.
This has been how I've worked with adapted lenses on 8 different cameras (3 manufacturers) over the last 10+ years where effectively exposure is automated. With shutter priority I've run into situations where auto ISO doesn't cover a large enough range leaving shots severely over exposed.

CHG_CANON Loc: the Windy City

I agree with Aperture Priority (Av). The camera will try to stay at ISO-0100 even in AUTO-ISO. Alas, for my work, this tends to be too slow for moving subjects or too slow even with the IBIS in low-light indoors or from dusk through after dark. These are shooting at the extremes, where moving away from the extremes, Av has proven to me to be the better approach for ISO-0100 results in AUTO-ISO. To assure the camera knows how to bias the exposure, apply around +0.7 for the Exposure Compensation, the same as with a DSLR and a 'known' lens to the body.

Whether you fix the ISO or let it float in AUTO-ISO, the photographer still has to monitor the shutterspeed being selected by the camera in Av to assure the desired results. Or, as occasionally in my Tv configuration, monitor the ISO being selected such as when moving from bright sun to shade without adjusting my speed maybe having the camera jump from ISO-1000 to ISO-3200 and grain that is visible even in the EVF.