I've just noticed that the last couple of days photos with my Sony Alpha-100 are pretty grainy when you view them full size (or even when you don't). Most were shot at ISO400, with some tonight at ISO100 and long exposures (2s, 4s, etc.).

The camera is nearly 3.5years old, has seen loads of abuse in my camelbak, stock lens, etc. Wondering whether its on its way out 🙁 Maybe because I'm fiddling more with manual settings (i.e. changing white balance manually) that I'm causing it? This is an example, click for the full size pic. Not great for an SLR, right?

Not sure what's worrying you. Could be sharper I guess. Was the SSS turned off? It should be as it's on a tripod. Any wind to move the camera around during the long exposure?

The font of all Sony knowledge is Dyxum, I'm sure you'll get lots of knowledgeable feedback on there.

Doesn't look too bad at all, I am almost tempted to ask: 'What noise?'

Might be some processing artifacts. Are you shooting jpeg or RAW?

Unlikely that ISO noise performance will get worse so I wouldn't worry, but long exposures will introduce a wee bit more noise, even at low ISOs.

Also, if you are manually exposing and stuff, and are maybe a wee but underexposed and then have to drag up the exposure after (esp in jpeg, but will also happen in RAW) that will massively increase noise. Try to 'expose to the right'.

Don't know if any of this helps, be good to know your thoughts. However, if you are looking for an excuse to buy a new camera, I will tell you whatever you need to hear 😀 . Sony 900 looks lovely, some really nice lenses also.

Kev

Yeah, another example here (excuse the ugly ginger bloke 😉 ):
http://www.flickr.com/photos/gingerfox/4266861286/sizes/o/in/set-72157623189796988/

I shoot in JPEG, and its never been an issue before, to be honest, although yes this is the first time I've used a (proper) tripod. I think the SSS was turned off for the photo linked above, but no it wasn't for the castle photo.

And the last thing I need is a new camera! Might treat myself to a new lens though 🙂

There's some noise in the face and shorts. I'm not convinced it's not a normal amount for an a100 at iso400.

Rather than get a new camera try shooting in raw. Raw Therapee is a good converter (and free).

Having looked at the extra properties of your pic compared to other Flickr users, the only difference i can see is perhaps the dpi and image size that the camera is saving. It might be worth checking that the camera hasn't defaulted back to lesser image quality settings. My Fuji for example when the battery is changed looses all its settings and reverts back to low quality images so more pics can be taken. Something simple but definitely worth checking!!

Other than that, some excellent shots keep up the good work

Dave

Try using RAW but for an A100 at 400 ISO it does not look like excessive amount of noise.

i've noticed (i think) an increase in noise at very low temperatures, camera body must have been nearing freezing point or below at the weekend and to my eye noise was worse. Without specific controlled experiment it is only subjective on my part though

In theory, noise should reduce with lower temperatures, although I'd be surprised if there was any discernible difference.
On most consumer cameras, IME ISO400 is about the most where noise is "tolerable" (well tolerable for me anyway).

I'm not totally up to date with the degradation of the sensor, but as far as i know the noise you have is nothing to do with age – if a sensor got damaged you would notice specific dead pixels, stuff like that.

Both of the shots that you show are in tough exposure conditions- the first a long exposure and the second with loads of snow.

Not wanting to say you don't know what you are doing, but I suspect that you used auto metering for both these images? in the castle image the camera has taken an average of the whole scene for the meter reading, but probably the difference between to street and the castle was about 4 or more stops, your image processing software has tried to compensate for this, but this inevitably means noise.

The second shot has all that snow, fooling the camera into thinking it's a brighter day than it was, again when you open in your software you try so get the face correctly exposed and end up adding noise.

So – solutions
in the first shot you could take the same scene either as 2 different exposures and blend them in photoshop (tripod perfect for this) for the castle you could also use manual focus to be sure of being precise. Or you could take 1 image using a neutral density grad inverted from the normal way and darken the foreground.

second shot just needs to be over exposed – unfortunatley there is no way of saying how much – a bit of trial and error in each case

Not wanting to say you don't know what you are doing

Please, go right ahead, as I certainly don't! Thanks for the tips. I could really do with a) a good photography guide book and/or b) some tuition.

The higher ISO rating you go the grainnier the pic will be.
Bring your rating down 100 and try, you may need to add a few secs
more but better quality of pic.

Long exposures will also add noise, whatever the camera. Most will have an inbuilt feature to automatically reduce it (my cameras take about 30 seconds to process a 30 second exposure, for instance).

also be aware even at low iso like 100, long shutter exposures will increase noise over an equivalent short exposure at the same iso.

there may be a point where the noise introduced by long exposures becomes more of a problem than that introduced by increasing the iso.

My D300 applies post processing to to reduce this noise which takes quite a while.

the shot you posted appears to have pretty good noise levels for a 4 second exposure, all i can really see is JPEG artefacts. Jpeg compression never deals brilliantly with levels close to black. I'd be pretty pleased with what you've got there on my D300.

curse my slow typing

Ah right, so what I think is noise is simply the artefacts from the JPEG compression? I'll try with RAW next time, although I think I might need a bigger memory card!

Long exposures will also add noise, whatever the camera

I think that will be only a very small amount, compared with what we normally think of as "high iso noise"

probably right DrJ