Grainy photos

[hedgepig]

Right, a quick primer on exposure, shutter speed and aperture.

The ides when setting your shutter speed and aperture is to allow the right number of photons of light to hit the sensor (or film!). If you allow more photons to hit the sensor by allowing the shutter to stay open longer, then you need to compensate for this by making the hole through which they pass smaller. Or of you make the hole bigger then you need to compensate for this by leaving the shutter open for a much shorter time.

So as far as letting less light in by using a smaller aperture ... this has to be balanced out by using a longer shutter speed. So when choosing a smaller aperture, you aren't choosing it because it lets in less light but because it has some other effect. Similarly, when choosing either a fast or a slow shutter speed, you aren't doing this because of the effect it has on the exposure, but because of some other effect that the shutter speed has.

So:
Small aperture - large depth of field
Big aperture - narrow depth of field
Slow shutter speed - records motion as a blur
Fast shutter speed - "freezes" motion.

I've already shown you examples above where I used aperture to achieve an effect. These next two photos show where shutter speed have different effects:

Here a fast shutter speed was required to freeze the bird (an incidentally to achieve the high shutter speed I needed to shoot wide open thus giving a limited depth of field!)

In contrast, in this image a slow shutter speed was used to allow the water to appear more natural.

Oh, and thank you for your comment on website, very kind of you.

 

[scanker]

Good stuff. Great explanations. I too have looked at your website in the past - gives me something to work towards! (if only)

 

[Womble_Lancs]

Hedgepig, you are a star. I really appreciate the time you've spent in typing this out for me! I think a huge penny has just gone 'clang!'

 

[Womble_Lancs]

I've just had a look at some pictures I took a couple of weeks ago, and I think I do need to use a smaller aperture. I have one picture of a toad, where the body is sharp but the head is blurred, and another which is the other way around, so obviously the depth of field is wrong.

It's a bit annoying really, because I have tended to leave the camera set on auto, which isn't producing the right results.

 

[hedgepig]

No worries Womble - happy to help.

With regards to the frog and using your camera on auto:

With animals (or people) you don't need to have the whole animal in focus as long as you have the eye pin sharp.

Full auto should be avoided - start working on aperture priority and shutter priority and then when you feel more confident you can start using full manual!

Neil (Scanker) - glad you find inspiration there!

 

[Womble_Lancs]

I've used manual focus a few times, but I don't trust my eye

I've used full manual shutter and aperture a few times with auto-focus, but only to try it out to see what the different settings look like. I wish I had more time to practice properly.

 

[hedgepig]

Oh, go ahead and use autofocus - trying to focus manually without a split screen is quite difficult.

As for practising - best way to learn

 

[Wayland]

Missed all this but it looks like Simon has it all covered anyway.

If you haven't checked out his website yet, why not?

Some great stuff on there.

 

[scanker]

Now you are here, Wayland.....that famous photograph of yours....would you mind revealing the settings you used to take that photograph please? In particular, are you using neutral density filters in order to use slower shutter speeds to get the water effect, or was it just a matter of the light available at the time of day? As a guideline, at what speed will water get that bridal veil effect? Thanks.

Just noticed I need one more post to get 2000. I'd best make it a good one.

 

[ZDP-189]

Yes, use a lower ISO on a tripod with a medium to wide aperture for adequate depth of focus balanced by better light capture and process the RAW in Photoshop Bridge then balance the levels and judiciously apply a noise filter. You may also consider bracketing that photo with 1 1/3 exposure stops and applying a High Dynamic Range merge. If you have one a better camera body and glass will give you more depth to play with.

 

[Womble_Lancs]

Sorry ZDP-189, you speak in tongues!

I've clicked with the DoF and I can do the bracketing, but I'm still learning Photoshop, don't have much time to play with it at the moment, so it's a slow process.

I will get there, eventually.

 

[shep]

I agree with everything above. The other thing to add is that many cameras have a long-exposure noise reduction feature. This takes the picture and then exposes a blank frame for the same length of time. It then subtracts the noise on the 'blank' picture from your night shot and improves your results.

Beware in-camera noise-reduction in the form of simple smoothing. It usually muddies your details. It's far better to take a noisy picture into photoshop or similar cheaper software and do your noise reduction there.

If the chromatic noise looks naff, consider converting to b+w. Noise in B+W looks a bit like film grain and with the right contrast adjustment can make a fantastic moody shot.

And finally, I don't know what camera you're using, but in general, the larger the sensor the less noise you'll get. If night photography is your thing, it might be time to write to santa for that DSLR.

 

[Wayland]

Now you are here, Wayland.....that famous photograph of yours....would you mind revealing the settings you used to take that photograph please? In particular, are you using neutral density filters in order to use slower shutter speeds to get the water effect, or was it just a matter of the light available at the time of day? As a guideline, at what speed will water get that bridal veil effect? Thanks.

Just noticed I need one more post to get 2000. I'd best make it a good one.

I'm guessing about the photo you mean but moving water will start to look "milky" after about two seconds of exposure, or a bit longer if you are further away.

If the light is bright, I use a neutral density filter to reduce the light to the sensor.

If it is already fairly low light, such as the twilight shot near Saltsfjell, I usually just stop the lens down as far as it will go and keep the iso. low to get the same effect.

Hope that helps.

 

[Womble_Lancs]

And finally, I don't know what camera you're using, but in general, the larger the sensor the less noise you'll get. If night photography is your thing, it might be time to write to santa for that DSLR.

Erm, it IS a DSLR It's Pentax *ist DL2 - I bought it as a 'learner' model.

 

[Shewie]

Totally unrelated to bushcraft I know but this is one of the most informative threads I`ve read for ages. Keep it coming guys, I`m trying to absorb as much of this as possible.

 

[Womble_Lancs]

I agree, Shewie. I'm glad I asked My main problem is that I forget it all too quickly. Wayland went through all the depth of field stuff at the bushmoot, but I've had to do so much since then that the new stuff forced all the old stuff out of my brain

 

[shep]

Erm, it IS a DSLR It's Pentax *ist DL2 - I bought it as a 'learner' model.

That's a perfectly decent camera, ignore my last comment. The distinction between 'learner' or 'entry' is just marketing. The difference in sensor size makes the step to SLR important. After that you spend heaps for relatively fine improvements.

Down at 200-400iso I'm sure you'll see much less noise. You have to pay megabucks to get a camera that will keep noise down all the way up to 1600 and with all of the techniques mentioned above, you won't need to.

 

[scanker]

Thanks for the info Wayland.

 

[mortalmerlin]

Generally speaking with real film, the higher the ISO rating the more grain you will see. In digital cameras that traslates to noise since your not changing the sensor it's self as you would with film. So yes if you change the ISO value of the camera and use a longer exposure you will have less noise in the image.