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View Full Version : D90 noise tricks.



Park Edwards
09-22-2008, 10:37 PM
Seems to be a few tricks going around how to achieve a clean image. This is my experience and or trick.

First off, if you are using a zoom lens, don't. You won't get the cleanest possible image with zoom lens. You'll get somewhat possible clean footage, but nothing like you would with a prime. My opinion messing with a zoom and a prime.

I'll post some footage later, but I'll just give a quick overview what I did. It turned out pretty well.

I used a manual 28mm 2.8. Not the fastest, so I can only imagine what 1.8 or 1.4 will be like.

I set the +/- to negative 1.3(it's the button next to the index finger when holding it) Stopped the lens down to 8-11. Set the gain directly in the middle. (If it's the little play button then up and down, then that'd be my gain). Pointed it at something fairly well lit and white. Let the AE do it's work and once It seemed fairly lit I opened up the aperture to see what I liked best. Pushed the gain up or down depending on how bright or dark it was and seemed to be fairly nice and clean.

What I saw. Contrast gets pushed way up/down. Your blacks are crushed. I'm gonna play some more, but really want to try to get a faster prime. I also noticed it's either going to be fairly dark, or blown out.

Kholi, what lens did you have when you were outside. M42 or something? And what did you do to make it so clean? I seen you pointed it a car and pressed a button. I tried to find it on the longest thread in history, but no dice.

Kholi
09-22-2008, 10:38 PM
Play button up and down only brightest the screen.

I had an M42 Screw Mount SMC Super Takumar 50/1.4. I set the exposure in a hallway before I walked over to the car although I've done it successfully out in the street as well. You have to find a brighter source for night, instead of a darker source.

Park Edwards
09-22-2008, 11:21 PM
Have you tried it with slower lens? I don't have a lens that fast so I think that's why mine is still noisy.

NikonGuy
09-23-2008, 05:37 AM
When you point it at a bright source it lowers the ISO giving a cleaner image, but when you point it back at the scene and you dont have a fast enough aperture, the ISO probably gets increased again to compensate, making it noisy.

The scene might just be too dark to use f/2.8 and low ISO, so the camera raises ISO which increases noise.

I mean with my 50mm f/1.4 lens indoors in the evening, i have to crank the ISO to at least 1600 with the lens at f/1.4 just to get a shutter speed of 1/30 which is bare miminum to get a steady still image, so having f/2.8 would require at least 3200 ISO in dim light.

I'm not sure how this translates in video since i dont have a D90 yet. :(

Thebes
09-23-2008, 10:55 AM
First off, if you are using a zoom lens, don't. You won't get the cleanest possible image with zoom lens. You'll get somewhat possible clean footage, but nothing like you would with a prime. My opinion messing with a zoom and a prime.


In good outdoor lighting conditions I have some excellent test footage from a Sigma 70-210 f2.8 zoom. This is a modern zoom and known as a quality piece of glass, older zooms will have more aberration, less sharpness, etc.

Also, shooting many lenses wide open will not give you the sharpest possible results. Whether this matters at all at the lower resolution of 720p with funky sensor sampling I can't say. But, even with my primes I've often been shooting stopped down a little (f2, f2.8) to get deeper DOF, a 50mm f1.4 wide open in a head and shoulder shot may loose focus on nose and ears if you focus on the eyes... that's just too shallow for me.

Park Edwards
09-23-2008, 01:22 PM
Sorry Thebes, I was referring to indoor and outdoor at night. My zoom outdoor in daylight is fine, plenty of clean footage.

I'm still learning the controls. Where is this "gain compensation" button? I guess the play button/up and down only adjusts the brightness on the lcd..I thought otherwise. What are you guys doing to adjust gain?