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White Bloom.
moz 
12/8/08 1:18:57 AM
SuperHero
Titan


I guess that is what it is called...

I was taking shots of some heron yesterday and not one of the buggers turned out.

Heron are white, as in "I just washed myself in new Ultra-White Omo whitening powder with extra bleach" white.

Although there is lots of detail that I would like to be seeing, all I seem to have got is a white blur.

I tried a few differnt things (obviously not the right ones!) and even tried setting the camera to auto, all to no avail.

Any suggestions?


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Look at that... A bear... mining for coal.


Athiril 
12/8/08 7:34:50 AM
Titan

Post a sample?

Id suggest a faster shutter speed either via manual setup, or negative exposure compensation if you were spot metering or metering off something dark, though if you suddenly meter off the white when it turns around next time itll go all dark, so manual is best bet.

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North Coast NSW Photo Community Forums
http://photodan.com.au/forums/

hlass 
12/8/08 7:49:35 AM
Hero
Titan



Dude your dealer must have ripped you off.

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Well that's great, that's just fuckin' great man. Now what the fuck are we supposed to do? We're in some real pretty shit now man... That's it man, game over man, game over! What the fuck are we gonna do now? What are we gonna do?

moz 
12/8/08 6:47:23 PM
SuperHero
Titan


Quote by hlass

Dude your dealer must have ripped you off.



Thank you for that.



Athiril, you're speaking too fast for me again, dude! Remember, I am the Grasshopper, you are the bald dude with the funny eyes and the accent.

I was using basic settings, just point-and-shoot stuff.

http://i46.photobucket.com/albums/f121/mozworthy/P8094094.jpg

Maybe I just need a polarising filter?


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Look at that... A bear... mining for coal.


Athiril 
12/8/08 7:22:57 PM
Titan

No, you're just overexposed.

It kind looks like a flash was used... but exif says no flash.

Dial in some negative exposure compensation.

300m, f/5.6, ISO 100, but not shutter speed in exif? :S

Try doubing or quadrupling the shutter speed next time.

if it was 1/200 sec, then 1/400 sec and 1/800 sec etc...

or try moving to f/8 from f/5.6 for a shaper image, that reduces exposure, also could try moving from f/5.6 to f/8 then to doubling shutter speed.

...*deep breath* okay.

Exposure is made up of a few components.

Shutter Speed (Effective shutter speed for motion picture cameras can be derived from shooting frame rate and shutter angle and phase just as an aside..), shutter speed controls how long the shutter is open for, if it is open for 1/100th sec, it is recording everything that happens (including movement, hence motion blur or camera shake blur) in one hundreth of a second, hence long exposure star trails, light trails, water falls etc.

Aperture Ratio (f/x etc, x is the aperture ratio or f-stop, technically aperture is the wrong term, as aperture is the physical aperture of a lens, for example the aperture of a 50mm f/2 lens is 25mm, as you can guess, the aperture ratio or f-stop is the focal length divided by physical aperture).

Sensitivity (Expressed in ISO/ASA in still camera, film cameras and motion picture film cameras, ISO/ASA is interchangeable with film ISO, digital video may use either ISO or dB (decibels of gain, ie: amplification of the electronic analogue signal received from the image sensor before analogue to digital conversion, iso does the same thing but gives you a film equivalency rating ISO 100 on 2 different digital cameras may have different dB of amplification, and 3 dB of amplification may be different ISO equivalencies..).

And lastly, the amount of light present in the scene.

Stops are used in photograhy to describe exposure, exposure latitude, difference and other things (6 decibels ~ 1 stop).

F-stops first, the difference between f/2 and f/4 is 2 stops, thus 4 times the exposure difference (the hole in the lens @ f/4 is 1 quarter of the area of f/2), f/2 to f/2.8 is 1 stop, f/2.8 to f/4 is 1 stop.. 1 stop is twice the exposure difference (also 1 EV).

Shutter speed, 1/100th sec to 1/400th sec is 2 stops, 1/100th sec to 1/200th sec is 1 stop.

ISO/ASA, ISO 100 to ISO 400 is 2 stops, ISO 100 to ISO 200 is 1 stop.

(Also note that ISO 100 to ISO 800 is 3 stops, and not 4, as it doubles each time, so its 2^stops and not stops^2, same with f/2 to f/8, 3 stops, same with shutter speed).

So if I say 1/200th sec, f/8, ISO 100 and then I say 1/800th sec, f/4, ISO 100, they have the same exposure value (or same brightness if you will).

So If I tell you it's overexposed 2 stops, then you need to pull something back 2 stops, eg 1/800th sec, f/8, ISO 100.

In automatic mode, your camera will set all values, or may set all except ISO, which you can set.

In aperture priority, you set aperture and normally ISO too, and the camera sets shutter speed to find the "right" exposure (what it thinks is right).

In shutter priority mode, you set shutter speed and normally ISO too, very effective for selectively blurring or freezing parts of moving objects, which requires a specific shutter speed.


A slower shutter speed will let you blur objects along their path of motion, a faster shutter speed will let you freeze objects dead in their tracks.

A larger aperture ratio (f/4 is larger than f/8) will decrease your depth of field (range of focus, ie: you focus at point B and 1 metre behind and in front of point B is in focus, the rest blurring out where as using a smaller aperture might have 3 metres in front and behind in focus, a smaller aperture ratio can increase sharpness, and will increase depth of field (more in focus) wide angle lenses naturally have a large depth of field, telephoto lenses naturally have a narrow depth of field.

Sensitivity allows you to compensate for amount of light, increasing it to get more shutter speed or a smaller aperture if you need it, decreasing it allowing you to use slower shutter speeds and/or larger aperture ratios, if you still need a larger aperture ratio and/or slower shutter speed and yore at the minimum ISO, then thats when you need to use a neutral density filter, which is like dark sunglasses for cameras.

Now that you should have some understanding of these things and how they affect your picture, read your camera manual on how to use manual mode, aperture priority mode and shutter priority mode.

I'll also part with two "rules of thumb"

Sunny 16 rule.

An object under normal sunlight generally acheives correct exposure at 1/100th sec, f/16, ISO 100 <-- you can convert that to other ISO/Aperture Ratio/Shutter speeds with the info ive given.

Secondly, the general rule to avoid camera shake blur while hand holding with minimum shutter speed, is to use (at minimum) the inverse of the focal length, so for 300mm, use 1/300th of a second or faster. etc.

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North Coast NSW Photo Community Forums
http://photodan.com.au/forums/

LordBug 
12/8/08 8:35:31 PM
Immortal

I try to simplify.

Auto mode is bad. Don't make use of it, learn the power of Aperture priority, followed by Shutter and then Manual.

Now. What's happened with your photo is that your camera has correctly exposed for the trees, not the birds. This would be due to the exposure detection mode that your camera is using.

To overcome this, your options are:

Use Spot Metering. Metering refers to the camera taking a measure of the amount of light in a scene, and judging the best aperture/shutter speed. Spot metering makes the camera take this measurement from a very small spot of what can be seen. Using this mode, focus directly on one of the birds to see what the shutter speed is. Next, focus on the trees, and you'll see the speed that the Auto mode was most likely using.

Or an easier method is to use exposure compensation, until you're more used to your camera.

Basically, take the first snap, check the preview, and underexpose the shot by changing the EV (Check your manual if unsure of this term) to a negative value. Retake the shot and repeat, until the white birds are no longer blown out, such is one of the damn handy features of DSLRs.


The reason why this happens is because the sensors in digital cameras are nowhere near as able as the human eye. When faced with a scene with things poorly lit next to brightly lit things, we can still make them out, whereas a camera will either have one completely blown out (The birds in your photo) or the other almost completely dark.

That's as best as I can describe with limited minutes, if you're still in the dark about it (How punny :P), we can point you to many much better typed explanations of this topic :)

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Lord of nothing except my own dreams, so it's Bug to you.


I love you Sharleen *)

moz 
12/8/08 8:36:55 PM
SuperHero
Titan


The pair of you...

Are wonderful.

:)





Edited by moz: 12/8/2008 08:38:21 PM

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Look at that... A bear... mining for coal.


Mademan 
12/8/08 9:48:36 PM
Disciple
It's called exposure latitude. Or, when talking about digital cameras, lack of.

Even spot metering can cause this sort of incorrect exposure. the segemented meter has read the trees, as they are the predominant feature of the scene, and exposed accordingly. But reading the birds may cause the exact opposite - high under exposure. You should spot meter both and go for the middle ground to start with. And always check the photo you've shot. That's what the screen's for.

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Intel q6600 | Gigabyte X38-DQ6 | 2GB Kingston HyperX 8500 DDR2 | MSI nx8800GT | Logitech G15

"Oh, I don't mind...but the government probably will"

err0r 
14/8/08 4:02:40 AM
Overlord

Quote by LordBug
...
Basically, take the first snap, check the preview, and underexpose the shot by changing the EV (Check your manual if unsure of this term) to a negative value. Retake the shot and repeat, until the white birds are no longer blown out, such is one of the damn handy features of DSLRs.
...



This goes for all digital photography, not just DSLRs. In fact, this and the ability to check focus are the big benefits of digital in the first place.

If you use a P&S digital camera and don't check your exposure and focus after taking your shots then you'd probably be better off using a 35mm film P&S camera and asking for a CD along with the developed photos and negatives. At least this way you get a print (how many people end up printing their digital shots?), and normal film is much more forgiving of exposure. In fact, today's automatic development process will go out of their way to correct your exposure as well as they can during development.

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Athiril 
14/8/08 7:11:23 AM
Titan

I dont check my exposure and focus in a shoot, it slows me down :P

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North Coast NSW Photo Community Forums
http://photodan.com.au/forums/

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