Advice for (Kowa) anamoprhics on URSA G2

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KyleMcConaghy

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Advice for (Kowa) anamoprhics on URSA G2

PostWed Apr 07, 2021 4:05 pm

Hello! thanks in advance for your help. I'm about to start a feature and director wants to use Kowa anamorphics. While I'm excited to use that glass, I've admittedly strayed from anamoprhics for a variety of reasons on the URSA. I'm a bit concerned with how much of the image will need to be cropped. With the WA adapter, the widest lens i'll have in the set is a 32mm.

Any sense of how that equates to spherical focal length, when considering i'll have to chop off the sides of the frame to get a 2.4 aspect ratio?

Also, in general, any tips, advice, concerns using 2:1 anamorphics with the URSA mini G2?

Thank you!!!
Kyle
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dondidnod

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Re: Advice for (Kowa) anamoprhics on URSA G2

PostWed Apr 07, 2021 9:56 pm

The URSA has a 3K Anamorphic mode that records 3072x2560. It does a 6:5 crop of the sensor using a 16.9mm (w) x 14.08mm (h) window of the sensor. Once you desqueeze it, you have 6144x2560, which is the 2.4:1 aspect ratio.
The full URSA 4.6K sensor area is 25.34x14.25mm.
The crop of the 3K anamorphic window of the sensor is (3072/4608) .66667.
The conversion from the full width of the URSA 4.6K sensor to full frame is (25.34/36) 1.42.
The conversion from the full width of the URSA 4.6K sensor to full frame is (1.42/.66667 =) 2.13 FF crop for 3K.

For more information:
"Wouldn't a 32mm 2.0x anamorphic lens on an URSA 4.6K G2 at the 3K anamorphic sensor area be a 48mm (32/.66667) Super 35 equivalent or a (32 x 2.13) 68mm FF equivalent lens?"

Re: Atlas Lens - Orion Anamorphic
viewtopic.php?f=2&t=124376&p=682098&hilit=+68mm+FF+equivalent+#p682098

You would have twice the equivalent focal length in terms of the width displayed after desqueezing.
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dondidnod

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Re: Advice for (Kowa) anamoprhics on URSA G2

PostWed Apr 07, 2021 11:11 pm

I found this thread on Eoshd in 2017. I assume that the description of Super 35 is using a 4:3 sensor. "...very different solutions and very personal decision; I never liked SLR magic 2x artifacts and vertical flares, it's kinda soft wider then f4 while my Kowa 16H is pretty sharp @ f1.2 or f1.4 , but i guess it is more about your shooting, if it's run and gun dual focus is a very hard to deal with and SLR Magic will be definitely easier to work with cuz it's almost 'focus through', but flares and anamorphic properties look way better on Kowas, well, at least to me:) ...the SLR Magic, from the reviews and videos I've seen, has more modern blue flares. ...(Kowa 16H) Paired with the SLR Magic rangefinder, it's a really great and completely practical solution but you're still limited to the 85mm and up on full frame and 50mm and up on S35. ...the 16H doesn't have orange flares, I misspoke, it flares blue as well but it's a warmer less blue color that mixes with the source light more than the SLR Magic which tends towards blue colored flares much of the time. ...For adapters, your best results are F4 and up and F2.8 is the most practical wide open aperture I would recommend"

SLR Magic Anamorphot 2x vs Kowa 16H
https://www.eoshd.com/comments/topic/21 ... -kowa-16h/
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dondidnod

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Re: Advice for (Kowa) anamoprhics on URSA G2

PostThu Apr 08, 2021 3:26 am

I saw this post on Facebook - Jonathan Noor > Anamorphic Shooters Feb. 1, 2021
"...Kowa (16-H) on a GH5, taking lens was a Panasonic 42.5/1.2, Nocticron. ...This was an ideal combo for us: As wide as it gets without vignetting, fast, sharp..."

The Panasonic GH5 has a 4:3 17.3 x 13mm sensor that lends itself to shooting with a 2.0x anamorphic lens. You use the full width of the 17.3mm 6K sensor. When you use a 4:3 sensor, the image is 8:3 after desqueeze, for a 2.667:1 aspect ratio. You then crop the sides off to arrive at 2.4:1. The 17.3mm width becomes an effective (2.4/2.667=.9x17.3) 15.57mm.

The 16.9mm sensor width of the 3K window of the URSA is (16.9/15.57) 1.08542 wider than the effective width of a Panasonic GH5 when shooting 2x anamorphic. If everything scales the same, could a 42.5mm lens on a GH5 then have an equivalent angle to a (42.5 x 1.08542) 46.13mm lens on an URSA using the 3K mode?
Last edited by dondidnod on Thu Apr 08, 2021 1:07 pm, edited 1 time in total.
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dondidnod

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Re: Advice for (Kowa) anamoprhics on URSA G2

PostThu Apr 08, 2021 5:52 am

I found this in a search:
Nathan_H wrote:

"Looking forward to some more test in low light (FPN) with this G2
...Kowa 16H/8Z - 40mm on 3K Anamorphic works OK lots of distortion through. Not the sharppest but definitly has some character"

Re: Ursa Mini Pro G2 + Anamorphic 2x— Video + Stills
viewtopic.php?f=2&t=88510
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Nathan_H

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Re: Advice for (Kowa) anamoprhics on URSA G2

PostThu Apr 08, 2021 7:33 am

Hello Kyle,

What Kowa are you reffering to ? If you talking about adapting 16mm Scopes (KOWA 16H, B&H, 8Z etc) 32mm on the URSA is way too large to be used.

Max I can go with KOWA 16H + Rectilux Hardcore DNA is 37mm ish (with some vignetting at close focus and a closed down aperture).

As for the cine Kowa prominar (PL mount, rented), the set go as wide as 32mm (the rehouse from PS-Technics).
The 32mm is in fact is a 40mm with a wide angle adapter on it. I shot a bunch with those kowa, but never the 32mm, the 40mm has already some crazy distortion, with the wide angle adapter on to it to make it 32mm I don't think I would love it.
https://vimeo.com/nathanhenneton/showreel2019
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Aaron Green

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Re: Advice for (Kowa) anamoprhics on URSA G2

PostThu Apr 08, 2021 9:23 pm

I shot a music video a few years ago with the Ursa and Kowa prominar 40mm. Here is the l link of you want to see the field of view:


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