Why would I use a cheap, manual, APS-C lens on a top of the line, full frame camera? Why?

It's pretty obvious to me and everyone else in photography that there are two distinct kinds of photographers. One faction has the mindset that pushes them to do everything as logically as they possibly can. They will spend lots of time narrowing down gear choices until they find the one piece in each category that gives them the "best" set of compromises they can find within a price range which they consider acceptable. Barring any severe post purchase disappointment they will use the collection of non-overlapping equipment until the wheels fall off. They wax eloquent about owning the same gear for years and years which they believe gives them special and Mariana Trench deep knowledge of every square centimeter of their kit and it's firmware. They generally have every subset of the menus memorized and have spent days, weeks, years fine-tuning custom function buttons --- which are also completely committed to memory. 

And then there are the people practicing photography who like to have something different for lunch every day. Who don't own vacation homes because they want to go somewhere different each time. Who own more than one pair of dress shoes. Who like sticking their toes into new stuff and seeing just what they can do with it. 

News flash! There is no "best" camera and there is certainly no "best" lens. There are lenses that are highly corrected and extremely, clinically sharp and then there is a huge range of lenses, old and new, that have character, faults, foibles, weaknesses, odd strengths and, most importantly --- personality. 

The photographers who have NOT battened down the hatches, frozen their credit cards in ice cube trays and taken vows of new photo gear abstinence are sometimes drawn to eccentric optical solutions like fraternity boys are drawn to beer. Like republicans to authoritarianism. Like chubby people to fad diets. 

Like .... well, you probably get the picture. 

For these people (the second group) photography can be a serious undertaking but it's clearly leavened with a bigger amount of sheer fun. Of off center experimentation and with a huge dose of disregard for following the "rules" of engagement the more logical and economically wise photographers devise to homogenize the practice of photography and to make it "safe." Repeatable. Acceptable. Consistent. Codified. 

I bought two of the TTartisan 50mm f1.2 lenses because I wanted to see just how good a $99, made in China, totally manual lens could be. I bought one in the L mount variety and the other in the micro four thirds lens mount variety with the idea of using them on both (or all three) systems. I've used the L mount version on the CL for about six months now and have found it to be a very good lens with a few caveats. It does have a lot of barrel distortion and there are no lens profiles for it in Lightroom (which is my preferred "front door" for post production. You'll have to figure out a correction for the lens yourself. 

But recently I've been playing around with older, vintage 50mm lenses including a Nikon 50mm f1.4 (pre-AI), two versions of the Canon 50mm f1.8 FDs, as well as time spent with the Contax/Yashica 50mm f1.7. All are basically good lenses that work okay wide open and then clean up progressively as one stops down toward f8.0. Since most have ancient and simpler coatings than current products I find them to have lower contrast. Not desperately lower contrast but enough to be evident in side by side comparisons with more modern fifties.  They are also less resistant to flare.

A good measure of my ongoing interest in 50mm lenses likely stems from my early embrace of photography, a limited budget at the time, and the efficiency of buying a first camera "kit" complete with a normal lens (50mm). But I would also say that it's a very natural focal length which more or less replicates the way humans process seeing.

When I photograph with a modern 50mm lens I am sometimes underwhelmed because the lens is clinical and analytic in a way that doesn't allow room for a different technical interpretation. They tend to be very effective literal documentary tools but less appropriate for images that need some visual friction in order to enhance a different presentation process. 

I like lenses like the TTartisan 50mm f1.2 very much not because they are sharp and contrasty; which they certainly can be, but because they can also be flawed and curiously alluring for many kinds of images. I especially like shooting this lens in conjunction with black and white camera settings because the lower overall contrast, when compared to something like the Panasonic 50mm 1.4 S-Pro lens, enhances the feel of a longer range of gray tones and a gives an impression of a wider dynamic range because of lower contrast in the higher values.

As other reviewers of lenses have written, the TTartisan 50mm f1.2 seems like two lenses. When used at f1.2, 1.4, or even f2.0 there is lots of vignetting, lower sharpness in the corners and softer look overall. Stop the lens down to f2.8, or more obviously f4.0 or f5.6 and the lens becames more "modernly" sharp. Competitive with all my legacy lenses and almost even with a current lens such as the Panasonic 50mm f1.8 S. 

If I use the lens on a full frame camera at the "open gate" of the frame there is obvious and uncorrectable mechanical vignetting. But if one uses a full frame camera set to a 1:1 aspect ratio then the lens just covers that frame with slight optical vignetting (correctable) in the corners when used at wider apertures and no vignetting from f4.0 all the way to f11. But even used wide open in 1:1 the vignetting is correctable and when I look at the photo at the top of this post the effects of any vignetting are obscured by the distributions of tones away from the main subject. In that example, when using the lens wide open, I see the underlying strength of the lens which renders the statue beautifully, with restrained highlights and open shadows, which makes the file very malleable in post production. The image just below is an example of using the lens stopped down to between f2.8 and f4.0 which shows off the relative sharpness of the lens.

So, if I embrace the foibles and weaknesses of a lens like this as an aid to artistic interpretation why then would I mate it with a state of the art camera? Well, the Leica SL2 has a very high resolution EVF which aids in and adds pleasure to accurate manual focusing. Especially when combined with the ease of punching in to a magnified frame for very fine focusing. Then, the sensor resolves 47.5 megapixels at the full size of the sensor but it also delivers 31.5 megapixels of resolution at the square, 1:1 crop setting, which is ample for just about any use and is probably beyond the resolving capability of the lens anyway. 

Added to that is a very nice monochrome setting in the camera's menus which gives me a much better starting point for later tweaking of the files. So, lens with personality combined with a highly capable shooting platform makes for a nice blend of tech and art. What's not to like?

I was curious to see how the lens would handle flares such as potentially caused by

 the direct sun reflected off my favorite new downtown building. Here (above) is the full frame. 

While just below is a prodigious crop of the part with the sun reflection. I think the lens does quite well 

if used anywhere but wide open....

The TTartisan lens under consideration here is widely available under $100. That makes experimenting with one a low cost, low risk undertaking. With the pace of inflation this lens has become almost free.

My next trial will be of the TTartisan 50mm f0.95. Just because.....zero point nine five!