EOS 450D - Overexposed Cat...
Discussion
I'm still learning, but I'm stuck when it comes to taking pictures of the moggy. Each time I do, whether I'm in P or Auto modes, the image is massively overexposed. Here is an example:
This was taken today, in sunny conditions with a Tamron 70-300mm (4-5.6) lens. So what am I doing wrong?
Full size image, with all the camera properties can be found here:
http://www.forumula1.net/photography/IMG_1418.JPG
This was taken today, in sunny conditions with a Tamron 70-300mm (4-5.6) lens. So what am I doing wrong?
Full size image, with all the camera properties can be found here:
http://www.forumula1.net/photography/IMG_1418.JPG
The problem is that the metering system in your camera (or any other camera) is not that clever.
Metering systems tend to assume that, on average, the light intensity in the scene should be about middle-grey, so they adjust the exposure to make that happen.
If most of you picture is taken up with a black cat (or you're using spot or centre-weighted metering, and pointing the centre of the picture at a black cat), the metering system will try to make your cat grey and hence over-exposes. If you take pictures of snow you'll see the opposite effect - everything looks a bit dark and under-exposed.
You can counteract the effect by adding a bit of -ve exposure compensation, or just use spot metering and exposure lock - point the meter at something which you want to be exposed correctly, (that isn't black.... ), lock the exposure and re-compose. Trial-and-error helps (otherwise known as bracketing...).
Metering systems tend to assume that, on average, the light intensity in the scene should be about middle-grey, so they adjust the exposure to make that happen.
If most of you picture is taken up with a black cat (or you're using spot or centre-weighted metering, and pointing the centre of the picture at a black cat), the metering system will try to make your cat grey and hence over-exposes. If you take pictures of snow you'll see the opposite effect - everything looks a bit dark and under-exposed.
You can counteract the effect by adding a bit of -ve exposure compensation, or just use spot metering and exposure lock - point the meter at something which you want to be exposed correctly, (that isn't black.... ), lock the exposure and re-compose. Trial-and-error helps (otherwise known as bracketing...).
sa_20v said:
I'm still learning, but I'm stuck when it comes to taking pictures of the moggy. Each time I do, whether I'm in P or Auto modes, the image is massively overexposed. Here is an example:
This was taken today, in sunny conditions with a Tamron 70-300mm (4-5.6) lens. So what am I doing wrong?
Full size image, with all the camera properties can be found here:
http://www.forumula1.net/photography/IMG_1418.JPG
Did you go to Jessops by any chance?This was taken today, in sunny conditions with a Tamron 70-300mm (4-5.6) lens. So what am I doing wrong?
Full size image, with all the camera properties can be found here:
http://www.forumula1.net/photography/IMG_1418.JPG
First off, change the ISO, this was 1600 in bright sunlight, probably 200 would have been better. Also appears the flash fired - is this the case? In which case the min. shutter speed would have been lower, so more likely to overexpose. In order I'd:
- Check you don't have any exposure compensation dialed in.
- Check you've not got exposure bracketing on
- Ditch the spot metering on a subject like this
- Drop the ISO to say 200/400
- Ditch the flash until you are happy without it.
- Check you don't have any exposure compensation dialed in.
- Check you've not got exposure bracketing on
- Ditch the spot metering on a subject like this
- Drop the ISO to say 200/400
- Ditch the flash until you are happy without it.
Jeepers. Black vs 18% grey is one thing, but in sunlight with ISO 1600 AND flash I'm surprised you can see anything! Even the gloomiest weddings don't need more than ISO 800 with flash.
In full sun you can set your ISO as low as it will go. Take a shot on whatever auto settings you feel happiest with. Then find out how to view the histogram (see manual under 'H') and understand what it is, because you can't judge exposure from the monitor. Once you know how to interpret the histogram, you can dial in + or - EV to suit. Well that's what I do, no doubt others will have other methods
NB Your cat appears to be dead...
In full sun you can set your ISO as low as it will go. Take a shot on whatever auto settings you feel happiest with. Then find out how to view the histogram (see manual under 'H') and understand what it is, because you can't judge exposure from the monitor. Once you know how to interpret the histogram, you can dial in + or - EV to suit. Well that's what I do, no doubt others will have other methods
NB Your cat appears to be dead...
Cats' retinas have a reflective coating, so using flash equals red-eye times about a million.
As for getting the exposure correct, because CCDs have a (pretty much) linear response, most of the information in a RAW image is in the top stop, so you want to be getting the histogram as far over to the right as you can without blowing highlights, and then pull it back in post-processing.
Have a look at ronbigelow.com for lots of articles. This one in particular goes into the details of CCD response and how the luminance information is spread out.
As for getting the exposure correct, because CCDs have a (pretty much) linear response, most of the information in a RAW image is in the top stop, so you want to be getting the histogram as far over to the right as you can without blowing highlights, and then pull it back in post-processing.
Have a look at ronbigelow.com for lots of articles. This one in particular goes into the details of CCD response and how the luminance information is spread out.
Edited by Major Bloodnok on Saturday 20th September 10:36
sa_20v said:
Thanks again for all the advice - just to confirm the flash was off, but the ISO was a mistake. Have had a play with the metering today and haven't experienced the same issue - is spot metering best for only macro images?
Not really - It lets you focus the exposure system on a small part of the picture, so it is useful whenever you don't just want the camera to use an average exposure value for the whole scene. For example, if you wanted to take a picture of someone backlit by a window, you could use the spot meter to get just the right exposure for their face (which would be in shadow), ignoring the light coming through the window behind them.
Not sure what options you have on the Canon, but mine can do one of three. Either meter from the whole scene, or from just the area at the centre, or primarily the centre but also taking about 1/3 of the frame around it into consideration.
Because central spot metering considers so little of the image, you have to be sure it's pointed at the right thing for it to work.
Because central spot metering considers so little of the image, you have to be sure it's pointed at the right thing for it to work.
sa_20v said:
Thanks again for all the advice - just to confirm the flash was off, but the ISO was a mistake. Have had a play with the metering today and haven't experienced the same issue - is spot metering best for only macro images?
Meetering is a funny old thing.No one system is right, no one system is perfect. They all make mistakes and can all be usefull.
The trick is to know when you want to use each one, and when there going to get it wrong.
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