Exploring the TTartisan 75mm f/1.5 Lens: A New Classic

Fall is here, and so is my second blog post of 2024. I’m so productive, huh? Blog-work ethics aside, the reason for me doing a small blog post today is rather unexpected. I have some blog posts lined up for some other lenses and cameras, that I was actually supposed to blog about first. But last week something unexpected happened.

TTartisan announced a new lens for the M42 mount. Something quite unheard of in 2024, since there are no digital cameras with that mount. It is an old film camera mount from the 60’s and 70’s. But why on earth would they release something like that amongst their other latest offerings which has mainly been modern AF lenses? Well, the announced lens isn’t just any lens – it’s a new rendition of a legendary lens formula from Zeiss Jena.

The Biotar 75mm f/1.5

The Biotar 75mm f/1.5 is quite a costly lens if you want to find one in a decent condition these days. They mostly range from 1600USD and upwards. Introduced way back in 1939, the Biotar is still renowned for its very unique rendering. What makes the lens unique is the way it renders the out of focus areas, also referred to as “bokeh”. The Biotar 75mm f/1.5 was famous for delivering quite sharp center performance, while delivering a very unique “swirly bokeh effect”

A lot of other lenses back in the days had this trait, for instance a lot of the Petzval lenses, the Leitz Summarit 5cm f/1.5 and one of my personal favourites, the Helios 58mm f/2 44M (based off another Zeiss Biotar formula from the Biotar 58mm f/2)

You can read my oooooold reviews of the Helios HERE and HERE , which are some of the first serious reviews I did on this blog. They’re quite fun to read, and definitely gives you the impression that I REALLY like swirly bokeh which I do!

Anyway, back to the lens at hand, the TTartisan 75mm f/1.5

When I saw that TTartisan was about to launch this lens, I immediately contacted them to ask if I could try utilizing the lens not on any regular full-frame film or digital camera, rather on the Fujifilm GFX50R medium format camera. I think they were quite intrigued by the thought of that since they sent a sample to me right away.

I do own an old Fujica ST601 with M42 mount, so I will be testing the TTartisan 75mm f/1.5 on film, but for now I am way more interested in the rumors that I heard from other places online that the original Biotar 75mm f/1.5 covers the entire GFX sensor, resulting in an even more pronounced swirl effect. So all the images that you will see in this review have been shot on my lovely GFX50R with a K&F Concept M42-Gmount adapter.

If you want to get the swirl effect on your APS-C fujifilm cameras you can buy a focal reducer that will essentially give you the same swirl that you would get on a full frame camera. Way back in the day I wrote about the Mitakon speed booster in MD mount HERE, but there are many other brands that offer this kind of adapter. The big downside to these focal reducers is that they have optical elements in them that can vary in quality, so the performance of the TTartisan 75mm f/1.5 will be degraded somewhat. That’s just the compromise of shooting this lens on an APS-C system.

So let’s get to work, and let’s have a look at the TTartisan 75mm f/1.5

Disclaimer 1: I was not paid, nor asked to make this post by TTartisan. All opinions expressed in this article are my own.
Disclaimer 2: All images of, and from this lens have been taken by me and is not to be used or redistributed without my prior consent.

Build and feel

Immediately when you lift this lens out of its box you feel the sheer heft of it. It’s a big chunk of glass and metal. It weighs in at approx. 570 grams which is quite substantial.
The original Biotar was designed in 3 different housings during its day, originally in exacta mount and TTartisan went with the “fatboy” design, which was introduced as version 3 in the 50’s. It’s rather short, but quite girthy especially at the front of the lens.
At the back of the lens at the slimmer portion, you have your distance scale and DOF gauge. Moving towards the front you have a classic carved, riffled focus ring that is very smooth to the touch, well damped as easily maneuverable. The focusing throw from near to infinity is about 200degrees. The closest focusing distance is 0.75m

Right at the very front of the lens you have the aperture ring which is also riffled. It has very nice tension and feel – and most importantly, it is a clicked aperture. The range is from f/1.5 to f/16. It clicks in half stop increments from f/1.5 to f/5.6 and in full steps from f/5.6 to f/16. It’s a very nicely designed aperture ring control. Well done TTartisan!

The aperture iris consists of 13 rounded aperture blades for perfectly round specular highlights even when the lens is stopped down. The original fatboy Biotar design had 10-12 aperture blades depending on manufacturing, so TTartisan decided to step up the game a little.

The lens uses regular 58mm filters.

Near the back of the lens there are 3 small screws that you can loosen and rotate the lens mount for the markings to line up completely depending on your camera, adapter etc. Something that I’ve always found quite frustrating when using these M42 lenses is that they all stop quite unevenly when tightened. TTartisan fixed this with their solution. Very nice.

The optical design and build of the lens relies on the old Biotar formula. You can see the lens diagram printed in the manual that comes with the lens, and it’s the exact same 6 elements / 4 groups design that you’ll find in the original Biotars. I don’t think TTartisan made any form of alterations to that design at all.

Everything about the TTartisan 75mm f/1.5 build feels very well made, sturdy and well considered. TTartisan usually makes great built lenses but this is one of their best builds IMHO.

Image Quality and usage

So let me state something before moving onto the rendering of this lens. Some people hate the swirly harsh background with a passion while others, like myself, love it to death. These swirly bokeh lenses are NOT general purpose lenses, rather they are lenses that you use for different specialized tasks when you want to achieve a very unique look.

So what is this swirly bokeh, and why does it even appear? Well let me get into it without getting overly technical. (Since I’m not an optical engineer and my knowledge of optical systems is mainly based on the biophysics of the human eye)

The reason for the swirly effect is that your out of focus highlights or speculars often referred to as “bokeh balls” become more cateye shaped the further you get from the center of the image, resulting in the illusion that the background is swirling around the center of the frame. This phenomenon is often referred to as “optical vignetting” but it is actually the result of a term called “Sagittal aberration” – Basically it is uncorrected aberrations in the sagittal plane of the optical path.
In other words the swirly bokeh lenses are lenses that don’t do much to correct these aberrations, or in the case of some Lens Baby swirl lenses even enhance the occurrence of these aberrations.

So it’s not wrong to state that the lenses that produce this type of swirly bokeh are actually lens designs that do a bad job of eliminating aberrations.

In the case of the TTartisan 75mm f/1.5 there is a very sharp focus plane in the center of the image, it quickly becomes much softer because of aberrations about midway into the frame, and near the edges the focus plane doesn’t seem sharp at all. And when you decide to go beyond the intended coverage of this lens and shoot it on a medium format sensor, the effect becomes even more pronounced.
When stopping down your aperture this effect lessens. So you can have a perfectly sharp and optically balanced image corner-to-corner at f/5.6 with the TTartisan 75mm f/1.5

In conclusion to the above, the best way to use this lens to place your subject center frame. Be it far or near, it will be sharp as long as it’s kept within the central 1/3 of the frame. I did try to change it up a bit and place subjects towards the bottom of the frame, and sometimes it actually looked quite cool.
When I stopped down, this lens could be used as any other medium telephoto lens.

Do bear in mind, however, that when you adapt this lens to the GFX sensor size, you do get a bit wider field of view than you do on full frame. It equals approx. a 60mm f/1.2 full frame equivalent lens when using the GFX 0.8x crop factor. The lens covers the larger sensor just fine. There is vignetting of course, but it’s no where near a hard vignette and can easily be corrected in post. I would say it’s about a 2 stop lightloss at the corners.

The lens handles flaring really well. I was really trying to get it to flare and it took me 4 stop overexposure at an angle upwards towards the sun to get a tiny fraction of a flare. The coating sure is modern and very well made. It also shows in the fact that it renders much more contrasty than what seems to be the case with the older original Biotar lenses.
This is where I can definitely tell that it is an old formula lens in a modern production pipeline.

Conclusion and sample images

I was so very surprised when TTartisan announced this lens. I did not really know what to expect from it, other than the obvious promise of swirly bokeh. This lens really surprised me with its amazing build quality and its great high-contrast coating and flare resistance. The fact that it covers the GFX sensor just makes it all the more fun to use for me.
I cannot decide whether or not this lens is for you, but if you’re like me and like your lenses to be different from each other, to have character and unique traits that you can use to your advantage when creating your images, then this lens might just be perfect for you.

The TTartisan 75mm f/1.5 sells for $269USD

All samples have been shot on the Fujifilm GFX50R and the TTartisan 75mm f/1.5. They are RAF files that I have processed to my liking in Lightroom.