An interesting lens that I would not buy again. It's not that bad. But it's not all unicorns and puffy clouds either. What lens? The new TTArtisan 50mm f2.0 for full frame.

 

I've always been a sucker for 50mm lenses and this tiny disappointment won't deter me from taking chances on cheap lenses in the future. But first, what is it?

TTArtisan, a Chinese maker of manual focus/manual exposure lenses for cameras introduced this lens earlier in 2022. For a few weeks it was sold out on all the popular sites but is now more widely available. It's a simple lens that's claim to fame is being the smallest, most compact, lightest 50mm f2.0 lens that covers full frame and is available in a wide range of mirrorless mounts. And it costs a whopping $69. 

In many regards it clicks the boxes I think are fun for a lens like this. It's all metal construction. The focusing ring is smooth and well placed. The aperture ring clicks nicely and with authority as you move it around. And the lens is tiny. It's almost capable of making a Leica SL seem light and carefree when this lens is attached. Almost.

It has six glass elements in five groups. It features 10 aperture blades for happier bokeh. And one of the amazing attributes of the lens is that even wide open it is exceptionally sharp in the center frame and at f5.6 it's sharp everywhere but in the extreme corners. So far, no really bad news. Right?

But it seems to have a fatal flaw. If you look at the sample images just below the product shots I've posted here you'll see that the corners have a green cast to them. I first saw it in a few of the images I made with the lens at its maximum aperture of f2.0 and I thought it would resolve as I stopped the lens down but that didn't happen. The green cast stuck around. And against lighter, non-blue/green backgrounds it's very noticeable. Noticeable enough that I would not use the lens at all for any sort of commercial work. Or, in fact, anything that a paying client might see. 

I tried using the various tools in the lens correction palette in Lightroom but I wasn't able to wrangle the green cast out. The Sigma fp has a lens optics correction sub-menu and in that sub-menu called "color shading." You can calibrate a lens by aiming it at a uniform subject (white card?) and clicking the AEL button. Then you can name the profile for each lens. There are four slots to fill. Doing that helped reduced the green corner cast but didn't take it out altogether. And, even if it did work it would only work in conjunction with the Sigma fp and not other cameras I might have wanted to use with the lens. Keeping in mind that I was testing the lens using raw files so it's possible that their might be a Jpeg automatic fix in some cameras out in the market. I just don't know about them. 

Given that the lens is small, cheap and mostly sharp I'll keep it around and play with it when I'm shooting black and white. When you go monochrome no one can see your corners color shift.... As though that's supposed to be some consolation. At any rate I marched around with the lens yesterday so you could see what it's all about since it got a bunch of buzz last month. 

One more thing. The lens has some geometric distortion and there is no current profile for the lens in Adobe apps. I found that moving the lens distortion slider in Lightroom Classic to minus five (- 5) cleared up the majority of the distortion but it's not a simple concave or convex distortion pattern; there are some slight wavy lines that remain in spite of the overall correction.

If you haven't bought one of these but were considering it and asking my advice I'd probably steer you clear of it. That is, unless you were vitally interested in the getting the smallest and cutest 50mm lens currently on the market for mirrorless cameras of all kinds. Then it's between you and your camera. 

I'll test it one more time with a different camera body and also use the Jpeg format instead of raw to see if one of my other cameras can auto correct for that color shading glitch. No promises of success. But, still, $69.

TTArtisan uses metal lens caps that screw into the filter rings.

Some people absolutely hate them. I'm ambivalent. 

On one hand I like the way they look. But on the other hand I mostly just use them for 

protection in camera bags, etc. and when I'm out shooting the cap comes off for the day

and lives in a pocket till we're through with our adventures in photography. 

It's not like I'm putting it on and pulling it off dozens of times in an 

afternoon. So, there's that. 

this was my best correction for the dreaded green corners. 

But notice: the lens is sharp and well behaved otherwise. f5.6

See the green in the lower right and all along the left side of the frame?

Me too. 

I tried working out the green with a radial adjustment but only succeeded in 

turning the green to a darker teal.

Man. that guy has baggy pants...

Should probably eat more. Send cake.

(no. please don't...).

Obvious green cast in the bottom corners. 

OMG. So much green cast in the bottom left corner. 

Masked on the right by the green of the building trim.

Perhaps a taunt about my lens buying habits. 

Or a more general message about clowns. 

At least they are not mimes.... (See the movie: Shakes the Clown). 

visible green cast in all corners except where it is masked by blue sky in the top

right corner. Untenable to me. 

And this is the most obvious example of all. Green all along the left side of the frame

with emphasis on the bottom corners. And extending well into the frame.

Not a great performance. 

Glad I'm not looking for affiliate cash.