Any P4K ISO400 vs ISO3200 test samples?

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Dmitry Shijan

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Any P4K ISO400 vs ISO3200 test samples?

PostSat Oct 20, 2018 6:32 pm

Did anyone have some ISO400 (first ISO range) vs ISO3200(Second ISO range) DNG test samples?
Wonder if underexposed shoot at ISO3200 with recovered shadows in post may have more dynamic range than same shoot at ISO400?
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rick.lang

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Any P4K ISO400 vs ISO3200 test samples?

PostSat Oct 20, 2018 8:20 pm

The relationship between stops of dynamic range above and below middle grey are illustrated in a chart in the BMPCC4K camera manual. The maximum overall dynamic range uses the 400 band. ISO 100-200 devotes more stops to the shadows, but significantly less stops to the highlights.

ISO 400 4 stops above, 9.1 stops below
ISO 3200 3.7 above, 8.7 below middle grey

If your scene has important details through the shadows, shooting at ISO 200 or 1250 gives you at least 10 stops below middle grey. Both good choices. ISO 1250 seems to be a popular choice balancing dynamic range and noise for those situations where you need to use a higher ISO.

If your scene has important details through the highlights, shooting either ISO 640-800 or ISO 4000-6400 may be good choices. We haven’t seen much in those ranges to judge a best practice.



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Dmitry Shijan

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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSun Oct 21, 2018 7:53 am

Yes, those are theoretical values. but when shoot RAW all those charts and meanings are useless. I just use native camera ISO and boost or lower expose in post.
I mean that i was looking for high iso and low iso sample exposed same way to compare. I was thinking to test this viewtopic.php?f=21&t=65149 "boost expose and lower gain" method to extend dynamic range from underexposed shoots with high and low iso and compare how far they can go into shadow.

Actually i found some samples but those are not exact what i looking for:
There are different iso samples with red lamp clipping but exposed differently. Also there are bmpcc vs p4k indoors dynamic range samples but also exposed differently. BMPCC is 2 stops underexposed but when you recover shadows noise amount looks similar as normally exposed P4K. https://www.dropbox.com/sh/d6p9k043vnvv ... 4Aw-a?dl=0

Here are also high iso (ISO3200) samples slightly underexposed to preserve extreme highlights. Nose from recovered shadows looks far better than similar low iso (ISO400) samples
https://www.dropbox.com/s/87wr8c8tmjzpb ... s.rar?dl=0
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rick.lang

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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSun Oct 21, 2018 3:47 pm

Looking at your original post, is this what you want to see?

Expose a scene properly for with the camera set to ISO 400. Let’s pretend the exposure was T4 etc.

Then with the camera set to ISO 3200, expose the scene at the identical T4 etc.?

That’s underexposed an additional three stops. Then in post you want to raise the shadows three stops to compare noise?

Apologies if I’ve misinterpreted your request.


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Dmitry Shijan

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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSun Oct 21, 2018 4:18 pm

Not exactly. I mean two scenes that visually looks exact the same, but one shoot at ISO400, and another at ISO3200. Both shoot at same lens f-stop but difference in light compensated by adjusting shutter angle.
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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSun Oct 21, 2018 5:26 pm

Thanks, Dmitry. I’m sure someone with the Pocket4K camera will provide that shortly.


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Re: Any P4K ISO400 vs ISO3200 test samples?

PostFri Nov 09, 2018 11:18 pm

rick.lang wrote: shooting either ISO 640-800 or ISO 4000-6400 may be good choices. We haven’t seen much in those ranges to judge a best practice.
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I've received 3 of my cameras. I'm getting FPN (I think) from 640 - 800. I'll try and upload later today or tomorrow. 2 of the 3 cameras duplicate this result and the 3rd remains unopened as of right now. 400 and 1250 look incredible and 3200 begins to show noise I feel I may need to denoise. Maybe I'm spoiled as a long time A7sii owner.

I'm concerned I may have bad cameras as the results from 640 - 1000 are horrible and not useable under any circumstance.

I'll keep ya' posted.

c
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Re: Any P4K ISO400 vs ISO3200 test samples?

PostFri Nov 09, 2018 11:45 pm

I just found this video by Samuel H. From author comments both high and low ISO have similar noise level and similar dynamic range if recover shadows and add essential noise reduction.

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Re: Any P4K ISO400 vs ISO3200 test samples?

PostFri Nov 09, 2018 11:58 pm

The P4K handles over-exposure better than under. I don't think there is any good reason to under-expose it. You're just gonna reveal noise.

I've basically come to think in terms of it having 3 standard ISO's: 400 / 1250 / 3200 and one "extended" ISO: 6400.

I'm not saying that's how it technically works (I know it's not) but in terms of practical thinking to get the best balance of sensitivity and dynamic range, it's a good mindset. 400 and 1250 are no compromise. 3200 is a bit noisy, 6400 can be used if you have no other choice.
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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSat Nov 10, 2018 10:10 am



The 400 & 1250 noise seems pretty identical. 3200 is pretty impressive. Anything past 6400 is blasphemy.
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rick.lang

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Any P4K ISO400 vs ISO3200 test samples?

PostSat Nov 10, 2018 3:08 pm

Cris.Cunningham wrote:
rick.lang wrote: shooting either ISO 640-800 or ISO 4000-6400 may be good choices. We haven’t seen much in those ranges to judge a best practice.
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...
I'm concerned I may have bad cameras as the results from 640 - 1000 are horrible and not useable under any circumstance...


Cris, do you also feel ISO 4000-6400 are horrible similar to 640-1000? I don’t expect I’ll find a little noise at 3200 a problem, but I’d like another stop to 6400 and have it look pretty good. To keep what I mean by “pretty good” in context, I stopped using ISO 1600 for the most part on the URSA Mini 4.6K as I found it was too noisy.

I don’t know if you (or anyone else) have the Mini 4.6K to be able to judge the BMPCC4K at ISO 6400 against the Mini 4.6K at 1600.

Thanks for any guidance you can provide. I’m trying to plan how I’ll use the BMPCC4K for client shoots in December. Not easy when I don’t have the camera!

The other recent posts above seem more encouraging than your remarks. But I’m not sure Resolve noise reduction is an option for me as my iMac 2015 likely is not up to that task.


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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSat Nov 10, 2018 3:45 pm

rick.lang wrote:do you also feel ISO 4000-6400 are horrible similar to 640-1000? I don’t expect I’ll find a little noise at 3200 a problem, but I’d like another stop to 6400 and have it look pretty good


Oh, man. By no stretch is 640-1000 "horrible". Anything above 400 (to 1000) has *slightly* more noise (than 400), assuming the subject is suitable for exposure at the lower gain circuit (if you're shooting in the dark, start with 1250 or above!).

OTOH, there's no reason to shoot at anything but 400 in the lower range, since 640-1000 doesn't do anything in-camera that you can't do in post equally well. You clip at exactly the same f-stop, from 100 to 1000. The other values are just getting mapped lower or higher. But the sensor performance doesn't change, until you get into the higher circuit.

3200 has a bit more noise and contrast than 400 but is thoroughly usable. Higher values will depend on your tolerance for noise.
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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSat Nov 10, 2018 9:06 pm

Thanks, John. Always good observations. When I get the camera, I’ll give ISO 6400 a try. For much of what I do, I’ll be living in the upper band most of the time for client work. Personal stuff can go with ISO 400 most of the time.

I’ve decided to add the SLR Magic 1.33x-65 Anamorphot Adapter and that requires a minimum T4 setting for wide angles and higher for longer focal lengths. So whenever I use that anamorphic look, it’s going to need the higher band as I’ll likely be shooting T5.6 or T8 a lot. That does make the Adapter easier to focus. More on this in another thread. Just mentioned because I can use those few extra stops of sensitivity in the higher band.


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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSat Nov 10, 2018 9:55 pm

Low ISO Range
Image

High ISO Range
Image
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rick.lang

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Any P4K ISO400 vs ISO3200 test samples?

PostSun Nov 11, 2018 2:38 am

Very nice. Very nice. Although the far right does show more chroma noise on the blinds.


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Last edited by rick.lang on Sun Nov 11, 2018 6:06 pm, edited 1 time in total.
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Philip Lipetz

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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSun Nov 11, 2018 3:37 pm

Mark Grgurev wrote:Low ISO Range
Image

High ISO Range
Image


400 and 3200?
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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSun Nov 11, 2018 3:53 pm

Much of the high ISO testing I see is underexposed. Underexposure ALWAYS leads to extra noise. So here's a quick test at ISO6400 that is more or less properly exposed. (It's surprisingly tricky to create balanced lighting at such low levels.)

Graded + noise reduction:
Image

Original frame:
http://www.humcrush.com/grabs/6400/p4k-6400.dpx
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rick.lang

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Any P4K ISO400 vs ISO3200 test samples?

PostSun Nov 11, 2018 6:12 pm

Joe, well done. 6400 does look very usable with only a hint of an issue on the plaster wall in the shadows on the right. This looks better in terms of noise in the final image than Mark’s comparison of ISO 400 to 3200, but of course you don’t want to go to it unless you really need it.


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Re: Any P4K ISO400 vs ISO3200 test samples?

PostSun Nov 11, 2018 6:35 pm

Philip Lipetz wrote:400 and 3200?


The reason I said low ISO and high ISO is because the specific ISO within those ranges is irrelevant.

I forget what the ISO was set to in-camera. It might have been 400 and 1250 but in post I might have set them to like 800 and 4000 or something. Regardless, I exposed with the zebras. I exposed so that the highlights are clipped just as much in both.

As joe12south mentioned, a lot of people will set their ISO high and then expose for middle grey. That gives the illusion of more "highlight dynamic range" but all you're really doing is under exposing the sensor and bringing highlights closer to the midtones. If you're trying to preserve highlights then just expose so your highlights are just under clipping (or just started clipping if you have faith in Highlight Recovery) so that you sacrifice your shadows as little as possible and then choose whatever ISO you want within that range.

If you have a low dynamic range scene and your highlights are nowhere near clipping and you can give the sensor more light, then do the same thing as before. Bring the highlights to just under clipping and allow your shadows to get more light and then drop the ISO. That keeps them away from the noise floor and keeps them clean.

The one thing that's true about all sensors is that they like light. Giving them as much as they can handle will always give you the cleanest images.

Btw, for anybody interested. Here's those same images plus shot of the original BMPCC graded to kind of look the same. I didn't have a second tripod, a way to mount one camera on the other, or two lenses that allowed me to match focal lengths so this was the best I could do

Pocket 4K Low ISO
Image

Pocket 4K High ISO
Image

BMPCC
Image
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rick.lang

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Re: Any P4K ISO400 vs ISO3200 test samples?

PostMon Nov 12, 2018 7:03 am

Pocket4K low range and Pocket look quite similar, so hats off to BMD.


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Re: Any P4K ISO400 vs ISO3200 test samples?

PostWed Nov 14, 2018 10:13 am

Mark Grgurev wrote:
Philip Lipetz wrote:400 and 3200?


The reason I said low ISO and high ISO is because the specific ISO within those ranges is


Only if you are shooting raw, and I did not see that specified in the original post, so I assumed it could be ProRes

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