cactuspic Loc: Dallas, TX

Everyone’s photographic needs and budget are different so their cost/value decision is different. Canon made numerous quality EF lenses that still yield excellent images; and I did not mean to imply that everyone should get a gas attack and sell their EF glass. What I am saying is that the RF versions tend to be sharper and better corrected than their counterparts. Does it mean that the difference is enough to justify replacement? Not if you are happy with the result. I think we are in agreement. The cost of the new glass may outweigh the benefit most people receive by way of incremental increased performance, particularly if they are not shooting cameras in the 45MP range and printing large.

The sole point I was making is that the lenses of today resolve finer detail and are better corrected than their earlier counterparts were.

CHG_CANON Loc: the Windy City

We started with how best to use legacy manual focus lenses, DSLR or other options. Driving off the road for how much better are mirrorless specific lenses, measured in $$$$, is a rather unrelated tangent. Personally, I recognize all RF lenses are better than their EF counterparts. But, that difference is most pronounced at their widest apertures at a 1:1 to the corresponding EF lens.

For our OP and others, just getting the legacy lens to a modern MILC platform will breathe completely new and fresh life back into these SLR lenses. Most of these used MILC options will feature 24MP sensors, well matched to these legacy lenses.

Leitz Loc: Solms

Are you pretending that's a fact, or just an uneducated opinion?

Ourspolair

Mis-spelling of "Peak" - use focus peaking (a feature on most cameras with an EVF).

Charles 46277 Loc: Fulton County, KY

Cactuspic, you are certainly right because the manufacturers offer two levels (or more) of perfection for two different markets. For a large part of the photography world, the highest price option is hardly needed or justified, as greatness has been accomplished so manifestly without needing the extreme limits of specs. Galileo would no doubt have preferred a giant observatory with The Hale Telescope, but there are things that scope won't do. For a long time, photojournalism did not need superfine lenses and cameras, because the pictures were going to printed in papers or magazines.

Mike Holmes Loc: The Villages Fl

money

amfoto1 Loc: San Jose, Calif. USA

The headline of your post is "Using old Primes on modern DSLR and Mirrorless", but your experience is with them on a DSLR.

FYI, it's a little different... easier... using fully manual lenses on a mirrorless with an electronic viewfinder. Most mirrorless with an EVF have Focus Peaking to assist with manual focus. They also typically have Exposure Preview, where you can pretty well judge whether the exposure and make adjustments based upon what you see in the viewfinder. These things are available in Live View on some DSLRs too (your Canon 90D has them), but using them in Live View with the camera held at arm's length is nowhere near as efficient as using them in a viewfinder, which just isn't possible with the optical viewfinder of a DSLR.

Video shooters and vloggers who are shooting a stationary subject with the camera on a tripod, where both exposure and focus can be preset and don't need to change, are no different from shooting a similar subject with a DSLR.

It is possible to get auto exposure with those lenses, too. Put your camera in Av (aperture priority auto exposure) mode, set the ISO and aperture manually, and the camera will select a shutter speed that it feels will give correct exposure (use Exposure Compensation, if necessary). Another way is to put the camera into M (manual exposure) and turn on Auto ISO. You choose (preset) the aperture and the shutter speed, leaving it to the camera to select a shutter speed that will give a correct exposure. While not as convenient as in the other auto exposure modes, M + Auto ISO also has means of applying some Exposure Compensation, if needed (it has to be done in the menu, instead of using the dial on the back of the camera, since that dial is used for aperture control in M exposure mode, even though you can't use it for that purpose with a fully manual lens).

There are modern fully manual lenses, too. A lot of them are being made in China and some are quite good. For example, I've got Rokinon (Samyang), Kamlan and Meike lenses I use on a mirrorless camera (along with a vintage Tamron manual focus lens I've adapted). All have proven to be quite good and capable of making excellent images. I have replaced two with autofocus lenses, simply because the active, moving subjects I often shoot with them pretty much require it. My eyes also aren't as good as they were when I was younger, either! I will continue to use the manual focus ultra wide and macro lenses in this kit, because the types of subjects I shoot with them are more typically stationary, where manual focus is no problem.

Another thing that can help when using those vintage lenses on your 90D is a "chipped" adapter. Those are a little more expensive ($30 to $40), but will allow your camera's Focus Confirmation feature to work. Bob Atkins shows a photo of one of those at his website discussing using manual focus lenses on Canon DSLRs: http://www.bobatkins.com/photography/eosfaq/manual_focus_EOS.html. The "chip" doesn't make for autofocus or even provide means of controlling the lens aperture from the camera, but it does enable Focus Confirmation (note: you have to go in and set your 90D's AF system to One Shot mode and select an AF point while you still have a modern lens on the camera, because you can't change those things once it's removed or when the vintage lens is installed). Some of those chips also can be programmed by the user to record lens identifying info in image EXIF. It's only the lens focal length and max aperture, though.