Shooting at high isos

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mart77

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So i have a 40d and im still trying to get the damned thing (love it really) to take less noisey images at the upper end of its iso range, 800+ but more like 1600.

From what i have learned, and correct me if im wrong, the trick is to over expose the image and bring it down in RAW editing. The theory being that the dark areas hold more noise and by reducing the blacks you will have a less noisy image.

Well i did an experiment before with flash and i was quite pleased with using this method.

Id like to try and get good at this and without the flash as well.

My question is, is this the right method in general with the 40d, and is it possible to take less noisy pics than most get with this camera.


I really want to try and push the limits with it WITHOUT using flash.

Would it be worth just sticking the thing on iso 1600 for 2 weeks and trying to experiment with it, by force if you like.


any thoughts?

thanks
 
The technique you are describing is called Exposing to the Right (of the histogram). You can get optimum tonal range, and minimal noise this way, if the subject is amenable to a bit of over exposure without clipping. This is a good article on it:

http://www.luminous-landscape.com/tutorials/expose-right.shtml

But if your objective is low noise at high ISO, then the 40D is a good performer and some custom noise suppression software is probably the most effective route. Noise Ninja gets good reviews but there are various packages out there.

The best answer to noise is big photo sites on the sensor, such as with full frame cameras eg Nikon D700 and D3.
 
Am I right in thinking though... that if you are at a high ISO for whatever reason, and can still afford to further overexpose (probably using a longer shutter speed)... you could reduce the ISO instead...?
 
theMusicMan said:
Am I right in thinking though... that if you are at a high ISO for whatever reason, and can still afford to further overexpose (probably using a longer shutter speed)... you could reduce the ISO instead...?
Click to expand...

A very good point, MM! Intuitively, I would have thought that you'd be better off reducing the ISO and underexposing the shot as you can recover lost shadow detail from RAW better than you can recover lost highlight detail. :thinking:
 
I shoot 1600ISO with the 40D and don't find noise a great problem.
will read with interest the article though
however, for fast moving stuff like I tend to do, speed is important...so over exposing just increases the shutter length and is counter productive.
 
Here is a slideshow of four images taken with my 50D at 400, 800, 1600, 3200 ISO. They were shot raw and processed straight to JPEG in Lightroom with no edits, just resized. I have randomised the sequence of the shots. These were shot in open shade at an exposure setting for lighting 5.3 stops dimmer than direct sunshine - quite shadey! Can you tell which image is which ISO? The 40D should produce slightly cleaner files.

http://picasaweb.google.com/EezyTiger/50DBPN#slideshow/5353154474951885922

EXIF is in the images so you can take a look if you want to.
 
this is the thing tim, i cant produce those kinds of results, im really trying, and i did have a really good go at that thing you did with the flash with the bridesmaid with her tongue out.

http://www.talkphotography.co.uk/forums/showthread.php?t=143212

Is exposing to the right the correct way? so as to reduce noise but preserve detail, or is what theMusicMan said better.

am i lacking something in PP, i dont do much other than reduce exposure.

bit lost guys, thanks for the replies everyone
 
Exposing to the right is basically a sound approach, especially if you shoot raw. Of course, if you want to keep noise low then not only do you need to expose well (or to the right) but you want to keep the ISO as low as possible. If you run out of room with your aperture and shutter speed then ISO is the only thing you have left. So long as you stick to the ISOs up to 1600, and don't get tempted to go for H (3200), then it is worth increasing the ISO to maximise your expoure. e.g. if you were shooting people at f/2.8, 1/60 and 800 ISO and were well away from the right of the histogram with your scene then I would recommend bumping the ISO to 1600. Bumping the ISO is a real amplification of the light hitting the sensor. Anything you do in editing after the image is captured is just digital mathematics on the raw data. It cannot create new information that was missing from the shot at 800 ISO.

However, my advice would be only to use the "full stop" ISOs os 100, 200, 400, 800, 1600 and not the ones in between. In particular, never use the ISOs 1/3 stop above the full stop ISOs. i.e. never use 125, 250, 500, 1000. Those are "fake" ISOs. The camera actually shoots at the full stop ISO below and then digitally increases the exposure in the camera by multiplying each pixel data value by 5/4. That will make noise more visible.

I'm very confused about your fridge picture. You said in the first post....

This was taken in near darkness, very little ambient light at all iso 1600 and F4.5 shutter speed of 100 with bounced flash.
Click to expand...

....but the EXIF says no flash was used.

Anyway, the image you've posted looks processed to me. The colours are a fraction livelier than I would expect and there is some noise in the back of the fridge. Can you make the raw original file available for me to look at?
 
tdodd said:
Exposing to the right is basically a sound approach, especially if you shoot raw. Of course, if you want to keep noise low then not only do you need to expose well (or to the right) but you want to keep the ISO as low as possible. If you run out of room with your aperture and shutter speed then ISO is the only thing you have left. So long as you stick to the ISOs up to 1600, and don't get tempted to go for H (3200), then it is worth increasing the ISO to maximise your expoure. e.g. if you were shooting people at f/2.8, 1/60 and 800 ISO and were well away from the right of the histogram with your scene then I would recommend bumping the ISO to 1600. Bumping the ISO is a real amplification of the light hitting the sensor. Anything you do in editing after the image is captured is just digital mathematics on the raw data. It cannot create new information that was missing from the shot at 800 ISO.

However, my advice would be only to use the "full stop" ISOs os 100, 200, 400, 800, 1600 and not the ones in between. In particular, never use the ISOs 1/3 stop above the full stop ISOs. i.e. never use 125, 250, 500, 1000. Those are "fake" ISOs. The camera actually shoots at the full stop ISO below and then digitally increases the exposure in the camera by multiplying each pixel data value by 5/4. That will make noise more visible.

I'm very confused about your fridge picture. You said in the first post....



....but the EXIF says no flash was used.

Anyway, the image you've posted looks processed to me. The colours are a fraction livelier than I would expect and there is some noise in the back of the fridge. Can you make the raw original file available for me to look at?
Click to expand...


Hi mate thanks for the reply, all useful info, the flash i used is a jessops crappy one so i dont know if it would register in the exif but i can assure you i used a flash.

Not sure how i can make the raw availiable to you, im more than willing to, can i email it to you or something or do you have a suggestion of how i can get it to you.
 
Mart, you can use a free service like http://www.yousendit.com/ to send the file. Basically you "email" the file to someone but without using traditional email. What most people do is to email it to themselves and they get a link in an email that points to the file up on the interweb.

You can then copy and paste that URL into the forum, for all to see, or stick it in a PM to anyone you want to share it with.
 
Flashman said:
A very good point, MM! Intuitively, I would have thought that you'd be better off reducing the ISO and underexposing the shot as you can recover lost shadow detail from RAW better than you can recover lost highlight detail. :thinking:
Click to expand...
Shadow has less info then highlights It is not to Overexpose but have your histogram as far to the right as poss. you get less noise here to the shadows
 
Chaz Photos said:
Shadow has less info then highlights It is not to Overexpose but have your histogram as far to the right as poss. you get less noise here to the shadows
Click to expand...

yeah that was my understanding, blacks create noise or something along those lines.

tdodd im sorting something out will pm you this evening with a link. cheers.
 
tdodd said:
Here is a slideshow of four images taken with my 50D at 400, 800, 1600, 3200 ISO. They were shot raw and processed straight to JPEG in Lightroom with no edits, just resized. I have randomised the sequence of the shots. These were shot in open shade at an exposure setting for lighting 5.3 stops dimmer than direct sunshine - quite shadey! Can you tell which image is which ISO? The 40D should produce slightly cleaner files.

http://picasaweb.google.com/EezyTiger/50DBPN#slideshow/5353154474951885922

EXIF is in the images so you can take a look if you want to.
Click to expand...

Interesting, i was only able to spot the iso3200 shot, the rest were fine (at that size anyway)
 
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