Sirui 50mm T2.9

• Anamorphic Lens by Sirui
• Single Focus : Synchro Focus
• Mount: E, RF, Z, L

WE ASKED FOR IT, WE COLLECTIVELY THREW A TANTRUM AND NOW WE GOT IT! Was it worth it, though? This is the question I’ll answer while looking at Sirui’s new 50mm T2.9 FULL FRAME, 1.6X anamorphic lens!

No, it’s still not going to work on EF mount.

Sirui is back, now putting full frame in their sights after a successful APS-C set and a quick Micro Four Thirds detour. I’m quite impressed by their squeeze choice and how that has a ripple effect on the ideal camera for it!

Looking at the outside of this 50mm, the body has the improved construction seen in the MARS set, which feels much nicer than the original set. The body is all metal and glass, and - funny enough - this chonky boy looks heavier than it is, at 1kg or 2.3 pounds. The front threads are 82mm, which is better than a lot of DIY setups out there. The lens also features a ¼-20” slot at the bottom for support, but I don’t really care for it...

The lens comes in four different mounts, E, RF, Z and L-mount, and the one I have here is in L mount, because it goes on the only camera capable of squeezing the most performance out of the lens.

Iris and focus rings are geared this time, a more professional-video approach to their target users. Markings are in feet and meters, again using fractions of feet. Minimum focus is 0.75m or 2 and a half feet, which is 4 inches or 10cm shorter than the original 50 mil’s minimum focus. Again we’re looking at a synchro focus design and squeeze does change through the focus range.

The advertised 1.6X holds true for infinity, but the more you come towards minimum focus, the less squeeze you’re getting. At mins we see 1.51x. And, to be honest, this SOUNDS a lot worse than it actually is.

Speaking of off, 1.6X is an unusual choice to say the least. 50mm with 1.6x squeeze gives us a 32mm horizontal field of view. I’m wondering if Sirui is trying to take on Panavision’s Ultra Vistas...

The biggest downside of the increased squeeze factor compared to the 1.33X sets is that no cameras offer native 1.6X desqueeze. So the only way to accurately monitor the picture on set is using an external monitor that allows you to apply a custom desqueeze.

For in-camera, the way I’m going about it is using the 1.5X value which is “close enough” to not affect framing too much.

Still on the topic of 1.6X desqueeze, at first I was put off by the number, then it dawned on me that if I shoot open gate on the S1H, which has a 3:2 aspect ratio and desqueeze by 1.6X, I get exact 2.4:1! This gives me a ton of extra sensor area over regular 16:9 full frame video desqueezed at 1.6X and cropped back to 2.4:1.

If you’re filming on 16:9 full frame, you’ll end up with a 2.84:1 aspect ratio, which I consider to be a bit too narrow - it’s thinner than my favorite 2.66:1. So to bring your footage back to CinemaScope, you’ll need to crop the sides of the frame accordingly.

Taking another page from the MARS set, the coatings here a lot nicer than the coatings we saw on the first Sirui lenses. This reflects on the flares, which are much subtler and have a nice teal tone that can be influenced by the light source’s color. For example, a strong tungsten source will make greenish flares as blue plus yellow equals green.

The lens is a bit too sensitive to what I’m gonna call “area flares”, large high brightness elements such as windows or screens, or pieces of sky! These also produce streaks, as opposed to the “usual” point light behavior we see in most other anamorphics. I don’t know yet if I love this aspect of it.

It might be repetitive to say this by now, but this 50mm is super sharp at critical focus even wide open. Definitely an easier task when the maximum aperture is T2.9!

Sirui never cheaps out on aperture blades and that is good for bokeh. Here we have ten blades and the iris remains a clean enough circle throughout the range. This ensures we get smooth oval bokeh regardless of aperture value. Before anyone asks, I’m not making oval inserts for these ones! 1.6X is squeezy enough on bokeh!

This brings us to the lens’ weakest aspect, which is the “slow” aperture for today’s standards of f/0.95 lenses and the likes of super fast sphericals, especially when talking about 50mm, which is an “easy” fast and cheap lens, possibly using a double gauss design! We got full frame, but we lost a stop of light. Was that a good trade? I anticipate complaints!

Overall, this is an awesome lens, and it’s surely replacing my old Sirui 50mm - it’s funny to call a 2019 lens “old”. I like the stronger squeeze factor and I can live with the light loss in exchange for open gate coverage. Now I just wish they hurry up and release the next one!