Shooting Help (of the photgraphic kind)

[Noel]

I've had a Canon A80 Powershot 4 meg for a few years now and generally happy with it. Rallying is a big thing overhere and sometimes I take the camera with me.

As you can see I'm getting "whiteout" on the windows and some of the bodywork. Does not happen all the time. Is this caused by the weather, bright sky, angle of shot, by the bloke holding the thing, or settings on the camera? Perhaps somebody could help (don't be too technical...)?

TIA

Noel

 

[Paul Chapman]

Hi Noel,

Not really into digital photography but have done loads using conventional film. However, the problem, as you are finding, is that automatic cameras, despite the claims made for them don't really work. Exposure meters are calibrated to assume that they are looking at something equivalent to a mid-grey tone. If you look at your picture, the centre of the shot is a rather dark piece of the foliage behind the car. Assuming that the meter in your camera is 'centre weighted' (eg the majority of the reading was taken from a ,say, 60% spot in the centre of the picture) it would have read that as mid-grey whereas it was much darker. That would have been OK if you were photographing the trees, but you wanted the car.

The best way around this is to use the camera on manual and set the exposure in advance. If you don't have a manual setting, point the camera at something similar to the tone of the car, press the shutter button lightly which will lock the exposure and focussing, then when the car comes by, press the shutter fully.

Hope this helps :wink:

Paul

 

[ByronBlack]

You best bet, if you have a manual setting on the camera, take an exposure reading from the gray gravel/tarmac, this is near 18% gray which is what film is calibrated for, this should then give you a nice exposure.

IF however your still getting white-out from that method, notch your exposure an f-stop or two, and this will stop the white-out.

I did a C&G in photography a little while ago for film, but the theories should be sound for digital camera's. Let me know if that helps.

Doh! (Just read Paul's post and said pretty much the same thing

 

[SketchUp Guru]

Paul's given you some good information. Generally the exposure appears to be alright considering the range of values. You could reduce the exposure a bit which would help to give more detail in the light areas. Keep in mind that the foliage will get darker, too. Setting exposure manually--perhaps before the car shows up and then reduce it from what the camera tells you is correct--might help. You'd have to experiment on the amount of adjustment needed.

Another problem that comes into play here is simply that the window and paint on the car are reflecting the sky back at the camera. Much of that reflected light is polarized and the use of a poloarizer filter could help. You'd want what is referred to as a circular polarizer for your camera. It seems not all of these new fangled digital cameras appreciate having a polarizer dropped in front of them so you might need to experiment.

Shooting on an overcast day as it appears you have is good because the scene contrast is lower (the range from bright to dark is narrower) than on a clear day. The problem is, the scene contrast is still too high for the camera's pick up. You might look for ways to reduce scene contrast. This is difficult when you're shooting something like this but simple things such as changing your vantage point can help. Keep the sun (even if it is a cloudy day) at your back will help.

Finally, shoot lots and vary the settings a little. That way you're more likely to get the one or two great shots. Fortunately shooting with a digital camera is basically free.

Say cheese.

 

[Nick W]

What I see is reflections of the sky. Have you tried a Polaroid/Polarizig/Polarising filter? A cheap test to see if this is the problem would be to hold one half of a pair of Polaroid sunglasses (can you still get them?) in front of the lens and rotate it around a horizontal axis.

See here for an illustration of the effect.

 

[Paul Chapman]

Hi again Noel,

I know you said "Don't be too technical", but it might be worth mentioning one other point, and that is contrast range. That particular picture is a good example of an extreme contrast range, from the dark foliage to the light being reflected from the car windows. If you assume that the contrast range is 1:100, your eyes can take all that in because they are adjusting all the time as you focus on different parts of the scene. However, the camera is not able to record such a wide contrast range and reproduce it without a considerable amount of intervention.

With conventional films and developers there are things you can do such as over-expose and under-develop and then when you get to the printing stage, burn in (give more exposure to) the over-exposed parts of the picture (in this case the windows). However, the fundamental problem is that the scene had a contrast range of, say, 1:100 but the paper on which pictures are printed or VDUs on which they are viewed are only capable of recording a contrast range of, say, 1:25 (I'm not quoting exact figures here). If you don't want to do a lot of messing about (and I imagine that with digital photography you can do a lot with things like PhotoShop, but I've not tried it) the best you can do is concentrate on getting the exposure right for the bit of the picture that is most important to you, and not worry too much about the rest of the scene :wink:

Paul

 

[cutting42]

Hi Noel

Firstly you have had great advice in the previous posts however A little bit of tech I am afraid as it will explain what is going on.

One thing you might want to try is to shoot under exposed slightly. On your Canon press the Func button select 0+/- with the up/down buttons and set it to underexpose by using the left/right buttons. You can set it to under (or over) expose by upto a factor of 2 in steps of 0.3, 0.6, 1.0 etc etc. These are called stops and tell the camera how to interpete the metering of the camera. Try setting to -1 and try it out, if this is too much try a little less and so on.

So why do you want to do this? Digital cameras have a limited dynamic range which are the number of steps between Black and White, if they hit these limits you cannot rescue the picture. If you under expose a little the detail might be hard to see but can be brightened up selectively with photo editing tools which came with your camera, free download (Picasa from Google) or very good value like Photoshop Elements.

Downside of this is that would need to edit all your pics on the PC before you show them, I do this anyway as it is part of the fun to me - my wife thinks I am crazy!

If you don't want to do this, Pauls suggestion of setting to manual is best or buy a camera with spot metering so you can meter on the cars not the scenery.

HTH

 

[devonwoody]

Noel I took the liberty of doing a touch up with paint shop pro 10, most probably a real technician could go further with an imaging program. I still think your original is a good photo it conveys speed and atmosphere of the occasion.

 

[Paul Chapman]

That's quite an improvement, DW - you're a bit of a wizard with this digital stuff 8) Something I'm not sure about as I've never done any digital photographic processing, are you merely adding density to the over-exposed windows or enhancing the actual image (eg if you went further you would actually be able to see the driver)?

Paul

 

[devonwoody]

Thank you Paul for your compliments, If I had original loading it might have been possible with curves/ histogram adjustments to obtain the driver, naturally you need to exclude manipulation from other areas of the subject whilst making these changes using a selection tool position setting. Then density is also added to other areas like kidding really.

 

[Noel]

Certainly an improvement Dev. Thanks everbody for your very helpful comments. I think I've got a grasp on things. Taking pictures of still or slowly moving objects are ok, it's just the fast moving things that get me. You've only got 5 - 7 secs or so to take a shot with rally cars so next time I'll spend a bit more time in getting things right.

Many thanks

Noel