Do you want a very well corrected, very fast, short telephoto lens for your medium format camera? Well then, don't get a TTArtisan 90mm f1.25. But......

I've been mucking around with full frame cameras for months now and, except for work, have been ignoring the GFX 50Sii that I bought mid-Summer. The camera is great. The sensor is great. The problem is with me. I just can't seem to pull the trigger and buy the lens I really should use with this system. That would be the 110mm f2.0. Rave reviews everywhere and at a full frame equivalent of 88mm it would seem to be the perfect choice for me. But for some unknown reason I'll continue to waste time and money looking for a "miraculous" low cost alternative while trying to convince myself that lens "X" or lens "Y" is just as good as the 110mm, if only I just put more elbow grease (and post processing) into the mix. 

The sad reality is that the Fuji GF 50mm lens and the 35-70mm kit lens are both really good performers; just not at the right focal lengths for me. So far I've mostly wasted money and time buying first the TTArtisan 90mm f1.25 lens and then the Mitakon 135mm f2.5. Both are available in both Hasselblad and Fuji medium format mounts. That would strongly imply that these lenses would be suitable for those camera systems. That they would cover the full frame of the MF sensor well. But....nope.

So, if perfect lens geometry is important be sure to pass on the 90mm. And, if zero vignetting is a must then consider both of these lenses as abject failures. Profound failures. I know this for sure now because I spent hours walking around yesterday photographing with the GFX 50Sii + 90mm, and another few hours staring at the resulting files in Lightroom and wondering just how much tolerance I really have for mostly crappy lenses versus just spending the money to buy the right stuff the first time. 

So, as pertains to the 90mm f1.25, what are my gripes? The universal black marks against this lens are threefold. First, it weighs a ton. Well, more like three pounds but that might as well be a ton if you are working a full day with this beast, handheld. Second, the vignetting is just awful. Amazingly bad. Stunningly bad. When I tried building a profile for this lens I found that +75 in the vignetting controls in Lightroom was just almost good enough. Really, +90 to +100 would be better. And here's the crappy deal with vignetting in a simply designed lens like this --- the amount of vignetting is variable and depends on the aperture setting and the distance setting. I guess that's true for a lot of lenses but this one goes from really dark but soft corners near wide open aperture settings to really dark but harder edged corner vignetting as you stop down. The final flaw is the easiest one to fix; mostly. It's the presence of a bunch of barrel distortion. You can correct most of it with a +7 or +8 increase in the distortion controls in post but you should also be aware that there are still mostly unfixable touches of "mustache" distortion that are not tamed by the magic of software corrections in most programs. 

One hopes that someone (Adobe or TTArtisan) will make a lens profile for this pudgy beast that actually fixes some of this stuff. But I think the market for the lens is so small that this will never happen. 

My next question, if I were a potential buyer, would be: "Are there any "pros" to this lens? Any conceivable reasons to buy and use one? 

Well, yes. 

Even wide open, at the center of the frame, the lens is very sharp. Stop it down to f5.6 and it's sharp everywhere. (But why would you carry around a three+ pound, ultra-fast lens if you need to shoot it at f5.6 to make it work? If you are shooting objects or scenes near infinity the lens works fine even at f2.0 and f2.8; except for the far corners. You'll still have to fix vignetting and distortion but in all fairness most lenses for current mirrorless cameras (Leica Q2 and Q3 included) lean heavily on in-camera software to make a lot of corrections to their lenses. A lot!!! The only difference, really, is that this particular 90mm is left to its own devices in use rather than being saved by intricate software fixes. If you had a "go-to" profile for this 90mm in your post processing program it might be a bit more popular. And perhaps more people would be walking around with bulging biceps from hand holding it all day long...

I keep the lens because I think it can be redeemed as a portrait lens. I've been using it to make controlled portraits with for a while and I actually have come to like it in these applications. I crop the images in camera to either the square or the 5:4 or 7:6 aspect ratios and the vignetting mostly goes away, along with a percentage of the frame. If you are a 3:2 fan you'll mostly remove the vignetted corners in that crop as well. The distortion correction of +7 works fine for all portrait work. A little, tiny bit of residual mustache distortion doesn't destroy portraits. 

It was a lovely afternoon here in Austin, Texas yesterday. Neither too warm nor too cool. Partially sunny but with fun clouds passing by. I took the lens out to see if I'd been blaming my own poor technique on the lens or if the lens was really as bad as I remembered. I shot a lot of frames. I walked a lot of steps. I took my time focusing and generally used the magnification feature to make sure things were really sharp. 

Here are some examples from the time spent with the lens. Please note that most of the frames have been mostly (but not completely) corrected for vignetting. The lens is fairly color neutral and I do like the center portion of most images shot with it. Just don't buy one for use as a precision architectural lens; especially if you intend to use it wide open. And copy work? Forget it. There are better options. Really. 

The one thing this lens is really good at is doing portraits with a wide open aperture and letting the background just vanish. That's its special feature. And that's probably why most people who buy one and keep one do so. It's a great look --- when it all works.

I'm in love with the Texas skies. When they behave as I'd like them to. 

I'm including this image because it's a great example of the center sharpness even when using the lens with the aperture at its maximum of f1.25. I focused on the center type and by the time I get to any corner it's just so out of focus. This was also shot at near the closest focusing distance. 

Fairly sharp at f4.0. Very usable.

this was shot long after the sun set and is a good example of a situation in which 

f1.25 can come in handy. The exposure was ISO 800, f1.25, SS= 1/13th. That's 

a pretty dark use case....

this was shot to show the bokeh of the lens at wide apertures. 

Notice the "cat's eye" bokeh in the corners. 

The sky changes so quickly just before the sun is gone over the horizon...

Holiday lighting at the Seaholm Power Plant. 

Same as every other year.