Lately getting alot of noise at low ISO

novicesnapper

Oh guys, I'm kind of stumped here. It feels to me the last few weeks, my camera isn't giving the shots it used too. Canon T1i with two kit lenses, 18-55 and 55-250mm. I have triple cleaned the lenses, no fog, no fungus etc and they are clean. I did a few outdoor shots today and just feel like they are too noisy, or is it me? I'm taking raw and jpegs at the largest setting/ 15 megs. At a setting of 100/200 ISO and f4 thru 10 or so, how much can I crop before roughly expecting to see some noise? I know that's rather subjective, but whether my eye is getting better or the camera/lens worse is a toss up at this point. The camera is a 15 MP, so it can put out some nice images. Should I go back in older images and compare? Time to clean the CMOS?

The images below are some from today. The original (bird) is dark, but was corrected PP, I knew it would happen because of the lighter sky behind. I guess this is about a 60-70% crop on a Canon 250MM IS zoom. Let me know what you think? Me or the camera? Edit to add> or my imagination? Thanks beforehand. :dunno

ziggy53

Imager noise has nothing to do with cleaning the sensor.

I'm not seeing the problem you describe, so I think that it's your monitor settings that are giving the appearance of a pattern that may look to you like noise.

Take the time to print a sample of the image to gauge how much noise is present in the image. Just crop out a portion that represents a 4" x 6" at 100 percent. Have that printed as a glossy print and use that print as your feedback.

Then never trust your monitor to gauge noise again. Instead, do a test print.

Edit: BTW, do try to properly expose for your subject, use the in-camera histogram and understand what the histogram means for your image. Proper use of the histogram is your best bet of obtaining proper exposure.

NeilL

If you are "correcting" very underexposed images like those above in post you will see a huge amount of noise, no matter the ISO. Nothing is wrong with your gear. Something like 80% of the data in shots like these is in the bits of sky and midtones. The bird will have comparatively no data to work with. Try to find out what you can expect from digital gear in general and your gear in particular. Work within their capabilities. You are the one taking the shots, not your camera. Your camera is doing what you make it do. Get some light in shots like these. Shoot bracketed exposures. Apply the zone system method of controlling dynamic range. Do NOT think, oh I'll fix it all up in post. It's not gonna happen!

Neil

rpcrowe

Noise and exposure
Noise is most apparent in areas that are underexposed.

I agree with Ziggy about noise patterns on monitors. I previously used a 21" NEC monitor and now use a 27" Samsung. The Samsung's image makes me think that noice has increased but, it is simply the difference in monitors.

Additionally noise is often increased if you sharpen the image strongly and when you sharpen also makes a diference.

novicesnapper

Wow, thanks guys, I did more digging on checking the cmos, and was just coming back to say I didn't think it was that lol. I do have a few specks, but nothing in the field I usually use, ie I tend to crop, sometimes zealously lol. My old lens was stronger than this and I still feel the loss of the power at times. I don't really trust this monitor to edit on, I found out it runs a tad dark. When I calibrated my other machines display, I could see a big difference between it and this one.

I knew I blew the shot on exposure lol, but was trying to salvage it. I had it on partial metering, I usually use spot, and think a point picked up some of the sky, fooling the sensor. I found that out about the sharpening awhile back, so if I do sharpen, I try to touch it lightly, ever so lightly, when I feel it needs that extra bit. I'm actually trying to explore more areas of the camera as I go, and each new menu has something to teach me lol. A good lesson in variables for sure lol. Thanks again everyone for the great tips!

Qarik

The best way to introduce noise in an image is to try an bring up exposure on a underexposed shot fyi

zoomer

Qarik wrote: »

The best way to introduce noise in an image is to try an bring up exposure on a underexposed shot fyi

...and then overcropping on top of that, makes it appear worse.

novicesnapper

Thanks all, I have went back to some basics. Rather relearning and breaking some old bad habits . I went ahead and changed bracketing for triple shots, just to make sure I got one of the correct exposure in questionable situations. I kicked it over to AV recently (aperture priority), and let the camera mostly control shutter speed (for now), until I get control of those bad habits lol. I have also, on manual, kicked it to 200iso at minimum, taking it to 400 at times, depending on conditions, my preferred iso was 100. My sis does portraits (av mode) and she would be lost on manual lol, basically she lets the camera pick up the slack after aperture setting and never felt the need to go onto other modes. I really hadn't thought until someone mentioned it above , that dark exposures are as bad as very light ones, but it certainly makes sense. Loss of data is killer in several ways. I really appreciate the responses and like I mentioned before, I learn every time I visit the forum. Thanks for that!!

On a side note the wife got me a plastic fantastic (Canon 50 1.8) for me to explore low light and shallow DOF with, interesting little beasty lol but fun so far. The learning curve train rolls along lol, at times lurching a little but making forward progress.