ProfHankD

Gotta disagree here. Canon is still using seriously outdated guts in most of their cameras, and that really hurts the M line. Of course, the old guts give Canon a big profit margin, are why you get...

Murdey and dash2k8: Coma isn't quite the same thing as SA: https://www.lensrentals.com/blog/2010/10/the-seven-deadly-aberrations/

Preferences are mostly a matter of camera settings or postprocessing with digital, but you'd like all your lenses to have about the same base color rendering so it's easy to match things. The ...

Bromberger: not an old lens user, eh? ;-)

SA is spherical aberration, which causes a halo-like effect around bright areas because the rays coming through the edges of the lens don't focus to the...

Ok, so they're making a 4-element fast 85mm for soft portraits. Nothing wrong with that (except maybe the price is a bit high).

However, why are at least some of their sample images so HEAVILY...

Seems to work with a SanDisk Extreme 90MB/s card. Stops erratically (with sound off) with two more cards, including an 85MB/s PNY card. This is completely unacceptable behavior from this Canon; the ...

Kodachrome... it gives such nice bright colors... everything looks worse in black and white. Yeah, it does.

Really sad to think that nobody has an alternative chemistry that could at least...

Yup, that confirms it's the lens. There's a slim chance this wasn't a lens design error, but an assembly error. You might check that everything seems correctly seated, etc. Sometimes, people will ...

Magic Lantern doesn't promise that it will not damage the camera, but it is very low probability -- I've never heard of anyone damaging a camera by using ML normally. ML hasn't been ported to any M ...

It's a little odd that the vignetting happens close up rather than at infinity and stopped down more than wide open. More than likely, this is internal vignetting from either the adapter or the ...

I'm getting that vibe too. No problem with other cameras doing higher bitrates on the same cards, but 5D IV doesn't like 'em.  Of course, various Sony bodies will not even give you the option of ...

A few quick eBay lens-buying hints: (1) Don't assume anything. Fairly often you'll see an ad for one lens with photos of a completely different lens, or a Pentax K mount body bundled with three lenses ...

They tell all you're likely to discover by this method: The good:  The lens appears well-centered and very evenly shaded (no bright ring); it's nearly perfect. The mild green fringe is axial CA ...

Just to check the "Doh!" case, you are turning the lens in the correct direction, right? Nikon is backward from most of my lenses....  ;-)

It's not that picky to get something for visual inspection (as opposed to a calibrated measurement). Closest focus, lens wide open, roughly centered and exposed to show detail within the circle ...

Yeah, locking pins often have a slight burr on them or the hole around them, and sometimes the spring that pushes it up pushes it a little too far -- not just a Nikon thing, but can happen on ...

Don't have an XL, but the Canon FDn 35mm f/2 works fine on my FD Speedbooster Ultra. If you're talking about an EF lens on an EF focal reducer, I'd be even more surprised if it didn't work... but ...

Just focus close and have the LED as far away as possible. The more OOF, the bigger the PSF image is and the easier it is to see structure inside it... and also the less critical the point source ...

Both haze and fungus would cause a minor reduction in overall contrast (which might actually be beneficial given Velvia's overly contrasty rendering, but I don't see it here). Fungus would also ...

I wouldn't expect greatness here; the odd 12mm Spiratone fisheyes aren't exactly razor sharp either. Diffraction limit should be around f/14 -- it should be best around that setting and with focus ...