Barry's Low Light Settings

T

THoff

Member With Answers
Yesterday I was futzing around with my camera in preparation of some low-light shooting that I might need to do later this week, and it was the perfect opportunity to try out Barry's low light settings. I extracted the settings from the corresponding scene file on the CD, integrated it into the scene file I was using, and read them from the SD card into the camera. I tried it out, and it seemed to work pretty well.

My shooting will be in 30PN, and that is the recording mode I had the camera set to. Just out of curiosity, I then tried the same settings in 24PN, figuring with 20% fewer frames, there will be that much more light hitting the CCDs, and low-light performance would improve.

To my complete surprise, the picture got darker. I made no changes other than changing from 30PN to 24PN. Does anyone have any idea what could cause this?
 
Maybe the shutter speed in relation to the framerate? You may need to adjust the shutter to an appropriate setting to be comparable to what it was doing with 30p.

Later,
Jason
 
The shutter setting didn't change, it was 230 degrees as per the scene file. Everything except the recording mode (24PN vs. 30PN) remained the same -- that's why I'm baffled.
 
Right. But what I am saying (and only guessing here) is that you might need to manually adjust the shutter to something that will act as the equivalent to 230 when you are in 24pn mode. Meaning 230 shutter won't look that same in 24p as it does in 30p.

What I am trying to think of may only be relevant to a video cam shutter though. It just seems I read something along those lines in Barry's book or something.

Maybe someone knows what I am trying to think of.

Later,
Jason
 
Wrong thread! Anyway--

Let Barry answer that, but I thought you need more light for more frames? Especially 60p? So, it should've been a bit brighter. Hrrm.
 
I've done some more testing with other frame rates, and what I observed yesterday holds true even for 60, which is a bit darker than 30 but definitely brighter than 24, at least for me. I'm totally baffled.

Has anyone else tried this?
 
Is it possible that when you switched to 24pn your shutter speed inadvertently was changed to the default 1/60 sec instead of your synchro scan setting of 230 deg? That shutter speed would provide less light than 30pn at 230 deg.
 
No, the scene file says "DEFAULT" for the "FRAME RATE" and "230.0d" for "SYNCHRO SCAN".

The only difference is 24PN vs. 30PN, and for some odd reason 24PN is darker.
 
I don'tknow what you're doing, but 24pN is definitely brighter than 30pN under those same circumstances. Are you swapping between two scene files? If so, is the gamma different? You can't change recording format by swapping scene files.

Here's how I tested it: set the camera in 720/24pN mode, film cam mode, frame rate to default. Then make sure "other display" is set to "partial" or "all" so the shutter speed displays on the LCD. Cycle through the shutter speed until the syncro-scan shutter displays 180.0d. Then go into the menus, into "recording setup", and toggle between 720/24pN and 720/30pN. It gets a tad brighter when going into 24pN, a tad darker when going into 30pN.
 
Agree,

Logically, and in fact, 24p IS brighter than 30p.

I use "Cinelike D" or "High" and it gives decent results.
I go up to 240.0d for the shutter speed and it looks OK.
 
I was not changing scenes files, the only thing that changed was that I went into the RECORDING SETUP and switched between 30PN and 24PN. The SYNCHRO SCAN was fixed at 230.0d by the scene file from the book.

I have noticed a (seemingly) logical increase in brightness in the past when switching from 30P/PN to 24P/PN, which is why I don't understand why I'm seeing something different with the scene file from the CD included with the book.
 
OK, we can put this subject to rest. I'm a knucklehead! (Duh!) :embarasse

There was in fact a difference in shutter speeds between the two settings, the 30PN used 1/30th, and the 24PN used 1/250th.

What is interesting about this is that I didn't change the shutter speed, only the frame rate through the RECORDING SETUP menu. Somehow, with the same scene file selected, the camera consistently selected 1/30th when using 30PN and 1/250th when using 24PN. On top of that, the scene file has the SYNCHRO SCAN set to 230.0d, so I don't know why the shutter speed was somehow independently remembered for the different frame rates.

So yes, Dorothy, 24PN is brighter than 30PN.
 
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