AC90: Blotchy detail?

M

metalshooter

Member
Hey Guys,

I've noticed when shooting with the 90 that often I get smudgy detail rendering is certain parts of the image. I know the aggressive noise reduction on this camera means that often less noise equals a softer/less detailed image but in certain shots it just doesn't seem to make sense. I have lowered Detail Coring and that seems to have reduced the effect but it's still something I'm noticing quite frequently. Is this simply a limitation of the codec or image sensor in general? Or is there something else I'm missing here? I'd be willing to put up with a bit more noise in exchange for the details not being so blatantly lost. I've attached a picture to demonstrate the issue. Thanks!

Detail_Loss.jpg
 
Thanks for the quick feedback Barry. I believe I was sitting around 15-18dB. (Less than ideal I know)

Am I on the right track in assuming that lowering Detail Coring even further would help maintain this kind of detail, with the tradeoff of a noisier image?

Thanks again!
 
A little, yes, but having that much gain is going to result in image degradation. You'd do far more for the integrity of the image by adding some light. 18dB is a huge amount of gain, and gain ruins image detail.
 
I'd make sure your shutter is never higher than 60 when shooting in situations in which you'll need to apply gain. It probably is at 60 but I'm getting it out their just in case. If it was it say 120 or 180 for example, the gain wouldn't have needed to be that high. Other advice would be to increase the lighting. One experiment you could try is opening up the window shades when it's bright out side although looking at your cat photo, that's probably what you did.
 
Thanks guys, yeah I forget occasionally that while the 90 doesn't have a consumer camcorder form factor, in regards to light sensitivity its comparable to one. Not knocking the value of the camera but I realized pretty quickly that going without gain indoors is next to impossible (shot an interview a few days ago and had two 400W Kino flows full up and still required a few dB to get the zebras in around 70..

As for shutter speed, wish that was the issue I shoot mostly in 24P and thus shoot everything indoors at 1/50 (and below when motion is non existent)

Thanks again fellas!
 
I've actually saw someone shoot something in very low light with a shutter that was at maybe 125 using a certain DSLR camera. Lest just say I couldn't believe it because I'm sure he had to increase the ISO by a bit to do that. This is why I'll sometimes bring it up just in case some people are using very high shutter speeds in low light situations.
 
Just remember that a DSLR that shoots reasonable video has a huge APS-C sensor or even a full 35mm sensor and it's unfair to compare that sensitivity with the 90's tiny 1/4.7" chips ... You have to remember that the 90 only has a base ISO of 40 so an APS-C sensor camera like Sony's EA-50 has a base ISO of 160 so it's already 12db ahead in low light. For the sensor size the 90 does an awesome job but you can't expect it to see in the dark like some 35mm sensor DSLRs ... Indoors simply be prepared to add some light so the gain is not so high and the cam doesn't have to apply so much noise reduction to the image and it will be sharp as a tack. When I still had my HMC80's I used to limit gain to 12db and the images were always great ...if the exposure was too dark then it's time to add some light!

Chris
 
Picking a different gamma setting could help also. Give B.Press or Low a try, I've found them helpful with this sort of detail issue.
 
Now this is the kind of stuff I really enjoy. New breed of camera, people posting questions, and many good folks chiming-in to offer suggestions to help. Great forum!
 
ChrisHarding said:
Just remember that a DSLR that shoots reasonable video has a huge APS-C sensor or even a full 35mm sensor and it's unfair to compare that sensitivity with the 90's tiny 1/4.7" chips ... You have to remember that the 90 only has a base ISO of 40 so an APS-C sensor camera like Sony's EA-50 has a base ISO of 160 so it's already 12db ahead in low light. For the sensor size the 90 does an awesome job but you can't expect it to see in the dark like some 35mm sensor DSLRs ... Indoors simply be prepared to add some light so the gain is not so high and the cam doesn't have to apply so much noise reduction to the image and it will be sharp as a tack. When I still had my HMC80's I used to limit gain to 12db and the images were always great ...if the exposure was too dark then it's time to add some light!

Chris
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If your referring to what I wrote, the video quality was very grainy in those outdoor clips (It was getting a little dark outside) and the f stop was no faster than f/3.5 since I think that was the limit of his lens and it could have been as slow as f/5.6 for those scenes. I do see that I should have probably given a little bit more detail earlier. I guess what I should have said is that if his ISO was indeed extremely high, lowering the shutter would have helped.
 
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You can tweak the scene files to get rid of some of the blotch gain. I personally find the scene files out of the box to be pretty lousy. Try the higher gamma setting and detail coring. Surprisingly you can get a pretty decent image in low light, but not straight out of the box. There's still the crappy looking 24p mode. Nobody should consider this camera if your main frame mode is 24p.
 
Mathew said:
You can tweak the scene files to get rid of some of the blotch gain. I personally find the scene files out of the box to be pretty lousy. Try the higher gamma setting and detail coring. Surprisingly you can get a pretty decent image in low light, but not straight out of the box. There's still the crappy looking 24p mode. Nobody should consider this camera if your main frame mode is 24p.
Click to expand...

Thanks! I'll take note of those particular parameters. Could you elaborate on your experience with 24P with this camera? I'm looking to shoot a mini doc this summer and was planning on shooting it in 24. I've heard about the choppy/trailing looking video but have not come across it in any of my footage thus far.
 
metalshooter said:
Thanks! I'll take note of those particular parameters. Could you elaborate on your experience with 24P with this camera? I'm looking to shoot a mini doc this summer and was planning on shooting it in 24. I've heard about the choppy/trailing looking video but have not come across it in any of my footage thus far.
Click to expand...

The "trailing" happens when you turn up the gain: http://www.youtube.com/watch?v=BgBA6mEhZ2s&list=UUD_UHXI6nB3CQiFCyMVYEGQ&index=3

It happens at all frames rates but is most noticeable with 24p because of the increased image retention.
 
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