Long Shutter Noise Reduction

[bertalan]

First, I apologize for not reading through the manual online, but you gentlemen are much faster! Anyways, is the noise reduction able to be turned off? My reasoning is for making night timelapses using ISO1600 with 30sec shutter and an interval of 35 seconds(the GXR does have the interval function right?). If so, does anyone have a 30sec night exposure without NR that you could share?
Thanks

 

[odklizec]

I'm afraid, the long shutter NR cannot be turned OFF in Ricoh cameras, which is a pity.

 

[ricohnick]

if you use raw, I think the noise reduction has no effect?

 

[odklizec]

Yep, the NR is not applied in RAW.

 

[ZDP-189]

In Ricoh cameras (the GRDIII at least) the NR cycle is compulsory for long exposures, regardless of whether the NR is on or off, you are shooting RAW or JPEG, and whether the ISO is over the Noise Reduction ISO or not. If you want to shoot intervalometer cycles shorter than that, you'll have to use a different camera or get creative (like shoot under and batch process the RAWs).

 

[setvak]

Bert, are you indeed asking about standard NR, or rather about dark frame subtraction (DFS)? If you ask about the later - I assume this is the case, as you are asking about taking 30s exposures at 35s intervals - no, this is not possible due to DFS, as the camera applies automatically DFS to any exposure starting from 4 seconds (2s exposures are the longest ones without DFS). For DFS the camera takes an image, closes the "shutter", and next it takes an exposure of the same length ("dark frame"), which is next subtracted from the first one. This way are "mapped-out" the hot or dead pixels, while real point light sources like stars remain.

Martin

 

[setvak]

Bert, are you indeed asking about standard NR, or rather about dark frame subtraction (DFS)? If you ask about the later - I assume this is the case, as you are asking about taking 30s exposures at 35s intervals - no, this is not possible due to DFS, as the camera applies automatically DFS to any exposure starting from 4 seconds (2s exposures are the longest ones without DFS). For DFS the camera takes an image, closes the "shutter", and next it takes an exposure of the same length ("dark frame"), which is next subtracted from the first one. This way are "mapped-out" the hot or dead pixels, while real point light sources like stars remain.

I just realized and checked that we discussed this issue here:
http://forums.dpreview.com/forums/read. ... e=27598707

However, you are (most likely) asking now about behavior of GXR cameras in this aspect ... in other words, if the GXR body and lensor behave the same way as all other Ricoh cameras. I assume that this may also depend on the unit attached to the body ... e.g. with the APS-C sensors the DFS policy might be different than with the small sensor units.

Regards,
Martin

 

[ZDP-189]

Bert, are you indeed asking about standard NR, or rather about dark frame subtraction (DFS)? If you ask about the later - I assume this is the case, as you are asking about taking 30s exposures at 35s intervals - no, this is not possible due to DFS, as the camera applies automatically DFS to any exposure starting from 4 seconds (2s exposures are the longest ones without DFS). For DFS the camera takes an image, closes the "shutter", and next it takes an exposure of the same length ("dark frame"), which is next subtracted from the first one. This way are "mapped-out" the hot or dead pixels, while real point light sources like stars remain.

Martin

For clarification, dark frame subtraction is what I was talking about, too.

BTW, is the purpose of your request for lightning photography? I guess that'd call for long exposures shot repeatedly. If so, I may I suggest two Ricoh-based options. (1) shoot 30s every 1min and 10s and just get a lower hit rate or (2) shoot multiple cameras coordinated by a single external intervalometer rigged to shoot two or more cameras alternately.

 

[setvak]

BTW, is the purpose of your request for lightning photography?

The same question (about DFS) applies also to timelapsing of auroras, night sky, etc. These types of night shots are one of the strongest arguments why I'm considering GXR + APS-C 24-XXmm for the future.

For lightning you can get along easily with 2s exposures in continuous mode, make the "dark frame" manually at the beginning (or at the end) of the sequence and use Photoshop batch mode for your own DFS, while processing the sequence.

Martin

 

[bertalan]

Thanks for the info. Yes, its the DFS that I am concerned about. On my Nikon D40, which I currently use for lightning, you can turn then DFS off with no real effect on picture quality. Not being able to turn it off is too much like my old film days when I had to use 2 cameras because it never failed that the best lightning would happen as I was advancing the film!