Rol Lei Nut

Not directly answering your question, but many Leica lenses were made in several, sometimes very different, versions. Usually without any clear labelling about which version a lens is. In the case ...

Leica R 21-35. It's not tiny, but still smaller and lighter than most 16-35 lenses. Very high microcontrast, completely parfocal, resists flare well and snaps into focus clearly on the A7RII's ...

I have a "Mengs", probably found with other names as well. No complaint at all: it fits both the camera and the tripod head well, allows easy access to the battery and other compartments and ...

That,,,

I like having f-stops on lenses and would generally pay something extra for that, all else being equal. But the Sony 35 1.8 isn't a lens I'm interested in, so the specific question is moot.

Perspective is set by the position. Whatever the lens used, the perspective is the same if the shooting position is the same. Field of view is determined by the lens. Basically, it crops the ...

Basically, no. On my A7RII (also have an A7) I happily use the following lenses which you have: Samyang 18, Sony 24-105, Sony 70-300. In the case of the 18 & 70-300, there seems to be quite a bit ...

If you do find a "Smart" LM=>Z adapter, keep in mind that the LM=>Sony FE one mentioned wasn't compatible with any of my Leica M lenses (its compatibility list is pretty limited).

What does it mean that "a lens can resolve 61mp"? All over the field? At all apertures? If both the former are meant, there might be (maybe) 2-3  consumer lenses actually able to do so. My take is ...

Works fine on an A7RII with both adapters. Based on general experience, on the IV it should work even better...

I have the Tokina. It's a lovely lens. For landscapes (long distances) it's almost as good as my very best short teles. Very nice bokeh and rendering. Its only serious drawback is that it's ...

What FL are you looking for? 50-60mm? 90-100mm? The latter is better for living creatures and can double as a portrait lens. The former is better for reproductions (copy work, paintings, etc.) ...

It would appear that Novoflex adapters for Sony FE and those for M43/Fuji X aren't built according to the same design parameters and possibly not using the same materials. My Sony FE ones ...

True. Lenses that get used often and are carried around without a cap on are probably at lower risk. Lenses which I rarely use, I put on a sunny widowsill for several days (capless  ;-)  ) every so ...

None of my Novoflex adapters (6?) has been the correct length. All have been about 0.2-0.3mm too short, evidently intentionally. You also mention light, which they're also not. They have the other ...

There is no quality control. Only if the person you buy it from is competent and guarantees, after testing and/or cleaning/adjusting, that it's a good sample (some shops and repairpersons do that). ...

Avoiding conditions in which fungus grows (humidity, darkness) is much more important than trying to prevent "infection", as fungus spores are all over the place anyway. That said, I try not to ...

Do most macro lenses have significant focus shift?

I have a number of UWA primes and zooms which are undoubtedly "better" than the Samyang 18 2.8, if rigorous comparative tests are carried out and the results examined at high magnification. In ...

I disagree that 18mm is too close to 15mm, there's quite a difference. 18mm is also a perfect complement for 24mm (the low end of your 24-105). The Batis 18 has a great reputation. If you want ...