Using a FF lens on a BMD 12K Ursa

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Using a FF lens on a BMD 12K Ursa

PostSat Nov 25, 2023 1:22 pm

Hello all,
at the risk of possibly opening a can of worms I want to ask this question. I have done some searching on the board and found a few answers but would like to hear some views.
I have the chance to get a Meike FF 35mm Cine lens for a good price but I'm hesitating as the Ursa 12K has an S35 sensor. I know it will "work just fine" but really? Will it? Are there any problems that folks would see as a deal breaker? I don't want to waste money on glass if it turns out to be a bad decision.

Looking forward to your views,
Thanks,
Jason
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Nov 29, 2023 12:22 am

What are you using currently when you short with the UMPro12K? I’d look for reviews and sample footage.

The UMPro12K can benefit from a lens with high resolving power, but how a new lens will look to you somewhat depends upon what you’re shooting with now. If you’re considering a lens that costs a few hundred dollars, don’t expect it to match a lens costing several thousand dollars. However not every shooting situation demands the highest quality lenses as there may be times when you want to use the Meike lens anyway… say when you’re not shooting a lens chart.
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Nov 29, 2023 1:00 am

It will work fine.

They are very much an entry level lens that won’t get the most from the sensor.

A lot of people use them, and great that you have a good price.

I’d personally stretch a bit more. Just like the grinder is more important than the espresso machine…. Lenses are everything and you should be thinking of them as long term investments. They can and should last well beyond your current camera. Higher quality sought after glass tends to hold its value even though they can sometimes be more than the camera price.

JB
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Nov 29, 2023 1:07 am

I can only second that. Didn't test a Meike lens on the 12K, but some very sharp classic Zeiss FF lenses.

They were great on the 12K too. One caveat though: some wides in FF try to balance the resolution in a way that they are sharp in the center and on the edges, but have a slightly softer zone between those. So, these would be the corners for you on S-35.

It depends on your style if you like that or not, some folks consider it quite 'cinematic' to have a tad softer sides or corners. And then, the 12K is biting sharp with a perfect lens, like an Otus, but in many cases you may want to add mild diffusion anyway to avoid that digital bite. Of course, with such excellent simulations as Scatter around, that can be done in post.

In short, there's no simple answer, but investing in great glass is a long lasting investment, just as John wrote. At least, if it's mechanical. We don't know about compatibility of electronic lenses in years from now.
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Nov 29, 2023 3:12 am

If the S35 version Meike 35mm uses a vintage roll off towards the edges for 3D pop, that might be a better option since shooting through a window of a FF lens will not have this feature. It's possible that it may be sharper as well on a crop sensor camera.

If you are using a crop sensor camera, is the investment in full frame lenses wise? The introduction of the Blackmagic URSA Mini Pro 12K showed us that none of the currently produced lenses have the resolving power to fully exploit the capabilities of a 12K sensor. If you intend to buy a set of lenses that are future proof and will serve you well for a lifetime, they aren't available yet.

Art Adams wrote:

"...An 8K S35 sensor would require a lens with more resolving power than an 8K large format camera as the photo sites are more densely packed.

Art Adams | Cinema Lens Specialist | ARRI, Inc. | lenses@arri.com"

r/cinematography Full Frame lenses on BMPCC 6k. Soft? Acceptably Soft? Crop Glass Better?

https://www.reddit.com/r/cinematography ... cceptably/

Re: The Blackmagic LF Camera - Is Full Frame ever coming?

viewtopic.php?f=2&t=135602&p=828097&hilit=+more+resolving+power+than+an+8K+#p828097

Tom Roper wrote:

"The problem is fundamental, inherent to the sensor size. To resolve the full pixels of the sensor, you take the horizontal pixels divided by twice the horizontal millimeters to get line-pairs/millimeter needed from the lens.

The lens for 12K footage on an (Blackmagic) Ursa needs to resolve 227 ln-pr/mm.
For 8K from the Ursa the lens needs to resolve 152 ln-pr/mm.

…Because the sensor out-resolves the lens by more with smaller sensors than large ones, the same lens on the larger sensor will give the higher overall system resolution, which is what counts."

Re: 12k Ursa Not Sharp When Punched In

viewtopic.php?f=2&t=145731&p=780841&hilit=+take+the+horizontal+pixels+divided+by+twice+the+horizontal+#p780841

In the reviews of the Meike 35mm T2.1 FF-Prime Cine Lens (PL Mount) on BH Photo, Jason wrote:

"...on my Red Gemini Looks fantastic...not over sharp like like my old Sigma art photo glass."

I could not find resolution test results for Meike lenses.

According to lenstip, the Sigma A 35 mm f/1.4 DG HSM resolution at F/4 is 38.8 lp/mm in the center, 31 lp/mm at the APS/C edge. At F/1.4, it is 47 lp/mm in the center, 36 lp/mm at the APS/C edge.
For comparison, the APS/C Sigma A 18-35 mm f/1.8 DC HSM 35mm resolution at F/4 is 54 lp/mm in the center.
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Nov 29, 2023 4:35 am

Don’t get distracted by resolution. It’s only one of many qualities we look for in lenses.

JB
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Nov 29, 2023 5:10 am

And if you are still fascinated by megapixels, have a look here at Steve Yedlin's tests:
https://www.yedlin.net/NerdyFilmTechStuff/

BM should haven written "Great Color" in bold on that camera instead of 12K.

"Many filmmakers believe that the best measure of perceptual image quality is to count the photosites on a camera's image sensor, but that is not substantiated by the evidence." Steve Yedlin
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Nov 29, 2023 5:57 am

At $6224.90 USD the Meike 35mm T2.1 FF - PL will look good on a URSA Mini Pro 12K OLPF.

But, wouldn't a Meike 25mm T2.2 Cine Lens for Micro Four Thirds on a BMPCC 4K at $1,694.99 look similar?
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Nov 29, 2023 10:42 am

That said, the analog medium of optics does not have a breaking point. Every lens EVER made will still produce an image that will be acceptable within expectations.
Perfectly said by Matt Duclos.

If we want to break down what's happening with FF glass on U12K sensor, the first thing we note is the image circle is bigger by 1.415x; the image is cropped. Light overspilling the sensor is being absorbed or scattered.

The relationship between light transmittance and lens resolving power is indirect but interconnected.

Light transmittance refers to the amount of light that passes through a lens without being absorbed or scattered. While light transmittance itself does not directly determine the resolving power of a lens, it plays a crucial role in overall image quality and can indirectly affect resolution.

What is resolution? It's the discerning of line pairs, putting a number to it in different ways. Visually is one way. Counting lines by eyeball depends on the visual acuity of the observer.

IMA is another way, machine automation but it's not counting lines, it's measuring contrast between them and assigning a number. We remember that when Duclos said the analog medium of optics doesn't have a breaking point, with IMA it does. It's called MTF. His point about an acceptable image within expectations goes into the number that follows MTF, 10,30,50,100. It's the percentage contrast result between the black and the white lines; e.g. 50 is higher contrast than 10. So we put a number to what is acceptable for the industry. In medical, microscopy it's 30. In astronomy, it's 10. In photographic 50 is customary.

Lens resolving power refers to the ability of a lens to distinguish fine details and resolve closely spaced objects in an image. It is influenced by factors such as lens design, quality, and aberrations.

Therefore, while light transmittance does not directly determine the resolving power of a lens, contrast is a critical factor in achieving optimal image exposure and realizing the full potential of the lens's resolving capabilities.
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Nov 29, 2023 3:46 pm

Tom, thanks so much for the lesson in reading those MTF charts. I knew how to compare MTF charts of different lenses to determine the ‘best’ lens but didn’t appreciate what those numbers meant.
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Nov 29, 2023 7:57 pm

Any lens will work on the 12K, even a pin hole. The thing to keep in mind is that the 12K can and will show the differences in lenses better than other sensors. Overall I would rate the importance of sensor number three, lens number two and operator number one.

Edit: 'Any' meaning any that can be mounted. Obviously some mounts will not work.
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Re: Using a FF lens on a BMD 12K Ursa

PostFri Dec 01, 2023 4:30 pm

Many thanks to everyone for taking the time to post replies, that's been very helpful. Sorry for the delay in coming back, it's been a busy week.
In the end, the FF lens option went away and I've ended up with the S35 version of the Meike 35mm lens. I haven't had a chance to play with it yet but I'm looking forward to giving it a test drive. I should add that the Ursa is a new camera to me so I'm at the foothill section of the learning curve, I expect I'll have plenty of other questions coming along.
Cheers
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Re: Using a FF lens on a BMD 12K Ursa

PostSat Dec 02, 2023 2:23 am

You're welcome to ask here. Have fun!
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Re: Using a FF lens on a BMD 12K Ursa

PostSat Dec 02, 2023 7:15 pm

I think medium format lenses will work better for the 12K
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Re: Using a FF lens on a BMD 12K Ursa

PostSun Dec 03, 2023 1:55 am

Why? Lenses developed for a smaller image circle normally have higher resolution.
But as I already wrote, resolution isn't everything and if you like the look of those lenses, there's nothing wrong with them. They are just a bit bulky and on the long side for S-35.
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Re: Using a FF lens on a BMD 12K Ursa

PostSun Dec 03, 2023 2:16 am

I’ve been using Mamiya 645 medium format lenses a bit lately.

I had them converted to PL with an inexpensive SimMod mount.

They are pretty small and very inexpensive.

Considering they cover beyond 135 format they are quite future proof too.

The only down side is that they are slower than a lot of 135 format glass and the minimum focus isn’t great on some of the longer lenses.

But they are optically great and I’ve used them in anger on films that are coming soon.

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Re: Using a FF lens on a BMD 12K Ursa

PostSun Dec 03, 2023 3:28 am

Uli Plank wrote:Why? Lenses developed for a smaller image circle normally have higher resolution.
But as I already wrote, resolution isn't everything and if you like the look of those lenses, there's nothing wrong with them. They are just a bit bulky and on the long side for S-35.

I mean Christopher Nolan used them on some of his previous IMAX movies. So if they will work for a 65mm film, they would work on 12k. I personally have been using them on my Pocket 6K. The amount of light these lenses bring in is more than the FF EF lenses I have used. I'm using 2-3 stops of ND for outside.
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Re: Using a FF lens on a BMD 12K Ursa

PostSun Dec 03, 2023 4:44 am

Who am I to argue with JB?
We have only a few old Rollei lenses, and I have already heard that Mamiya made great glass.
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Re: Using a FF lens on a BMD 12K Ursa

PostSun Dec 03, 2023 8:34 am

In my life, when I could, I ever tried to buy best lenses that I can afford.
Like told from John, the lenses’ value was keep in time more than that of cameras.

Usually I search a good sharpness at all open iris, but I’m not obsessed of that, I had sigma art for where I know that I should reframe, but often I contuse to use old but good canon 17-55 2.8 that had a good stabiliser in video, a bit less sharp than sigma, but give me work.

Coupled to x-h2 in 8k is a bit soft if you zoom 1:1 but hey who zoom so much? But I like its picture style :-)

To me the interest on 12k are for newer wwwrgb sensor and it’s color, when I will can, I will replace my old but good horse UmpG1 with a 12k but only for newer color fidelity.
Actually I can continue to have great picture and videos from my actual cameras and sigma/canon L series :-)

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Re: Using a FF lens on a BMD 12K Ursa

PostSun Dec 03, 2023 8:52 am

Uli Plank wrote:Who am I to argue with JB?
We have only a few old Rollei lenses, and I have already heard that Mamiya made great glass.


Ha it’s not like that.

For sure as you said wider lenses are hard to get or actually impossible.

Fast lenses are hard too. They tend to be slower. They tend to be primes. Mamiya do make some zooms too but I haven’t tried them cause I don’t like zooms :-)

But there are some really interesting lenses out there and because medium format prices crashed they can be had for a couple of hundred dollars plus an adaptor.

Contax 645 for the Zeiss made lenses are also pretty interesting.

I personally like shooting medium format film. I have a Mamiya 645 and a Mamiya 7 already so it was easy to vary those lenses.

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Re: Using a FF lens on a BMD 12K Ursa

PostWed Dec 06, 2023 12:36 pm

Hi everyone,

Interesting thread!!.

My two cents on this topic. I own the 12k OLPF, a FF Meike set and other Canon EF lenses, like the Sigma 18-35 F1.8, the Canon 17-55mm F2.8, etc...

The Canon 17-55mm F2.8 shows really bad vignetting on all corners when used with the URSA 12k, so did not include this lens on the comparison.

I did the comparison (not scientific test) between de Meike FF 24 T2.1 and the Sigma ART 18-35mm @24mm at several apertures and the result speaks by himself. Focus was adjusted manually on both lenses to ensure every time was as good as possible. The camera was 1,5 meters away from the CD boxes. Then imported the BRAW files into a 12k resolution timeline and exported the 12k JPG files using Davinci Resolve. In order to upload the pictures, I simply cut them using windows photo editor.

Sigma lens is sharper, the image has more contrast and it shows darker corners @f1.8 than the Meike @ T2.1. Both lenses show good focus @ F4 / T4 with little improvement @T5.6.

I`m really curious how the IRIX lenses look when used on this camera.

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Last edited by Diego Pohl on Wed Dec 06, 2023 12:51 pm, edited 3 times in total.
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Dec 06, 2023 12:40 pm

Here the pictures @F4 / T4
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Dec 06, 2023 12:45 pm

and here @F5.6 / T5.6
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Re: Using a FF lens on a BMD 12K Ursa

PostWed Dec 06, 2023 2:07 pm

Diego Pohl wrote:....
I`m really curious how the IRIX lenses look when used on this camera.


I have an IRIX 45mm T1.5 Cine lens in PL and it works fine on URSA 12K. Not as nice as Zeiss Otus 28mm but comparable and close with Sigma 20mm T1.5 FF which is a great lens.
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