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December 30th, 2008, 09:08 AM | #31 |
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For whatever it's worth, CA was a lot worse on the JVC HD100 (110,200,250) series.
The tele end at wide open you always had to be careful, especially under high contrast. |
December 30th, 2008, 09:54 AM | #32 | |
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My theory on this is that by using this sloping gamma curve you are compressing a lot of luminance information into a very small range of the 8-bit sample. The shifts in luminance are therefore being quantified a bit too much. There is simply not enough zeros and ones to describe the shifts in luminance. I am sorry if I did not manage to make my point clearly. English is not my native tounge. |
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December 30th, 2008, 10:29 AM | #33 |
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I honestly don't know the Vortex settings because I made the changes as I watched the video and did not write anything down. I don't even know what I changed it from... I couldn't go back to the default settings if I wanted (unless I used the reset all button). I'm pretty sure it's a CINE4 gamma and one of the black levels was lowered a bit. This is for the EX1 and not the EX3 though. If you don't have the DVD it's definitely worth it, at least it was for me. I still review it now and then, the more I shoot the more the other features it mentions makes sense. Sorry I can't be of much more help on this one.
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December 30th, 2008, 10:39 AM | #34 |
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Thanks guys for offering up such great help.
Simon, the zebras were ON - like I already said, and not one line showed up anywhere in the image at any point that I was recording. They were set at 90 though, not 70. Zero gain. Again, not one zebra line showed, histogram was safe, monitor looked 'underexposed' even, and it clipped, which is surprising to me to say the least, and which is why this post. Thank you for the shutter speed tips. They are my common practice, and actually how I shoot/shot every scene (30fps - 1/60shutter) minus the turkey vulture (where I added text in the video explaining that I had used auto shutter specifically there). Call me an amateur, but I find it useful when panning across the sky chasing a bird as he flies past the sun and back again. The Egret scene immediately followed the vulture, my bad for shooting the still of the monitor before I changed the shutter mode back, rather than after. If you will notice, in the still shot of the monitor the camera is not recording. I re-set shutter just after I took the photo/before I recorded the image. The Egret footage in the video is taken at 1/60th shutter. Your well trained eye can probably tell by the motion blur in the frame grab, right? Trust me, or not, my clipping issue - so far as I can tell - is not related to any shutter speed/techniques that I use. Alister, good on you for noticing the extender. I purchased it about a month ago and it was sitting in my pack fixed to the end of my still cam with the 400. Temptation was irresistible. I HAD to try it. However I only put it on at the end of the shoot, for the pair of Mallard ducks (in the video), and for this Egret. In the video, where the much smaller (farther) Egret walks across the dark background, I actually only had the 300 mounted. No extender. But to be honest it was pretty wide open for that shot. Two ND filters, 1/60th shutter, no gain and almost wide open. I bet if I had stopped the lens down and used 1 ND filter instead I could have reduced CA. I appreciate the critiquing of my shooting techniques everyone. Thank you. I hope to always keep learning. What my real point is here, is that on this particular camera there actually exists a HUGE difference in what my monitor is showing, compared to what is being recorded. Let me say that again - there is a huge difference in what my monitor is showing, compared to what the camera is actually recording.. So thank you Alister for pointing out that the histogram is not very accurate. That solves one mystery. Simon, could my NOT setting the monitor up by the color bars be causing/adding to this discrepancy between the viewed image and the recorded one? |
December 30th, 2008, 11:18 AM | #35 | ||
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Steve |
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December 30th, 2008, 03:26 PM | #36 |
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[QUOTE=Eric Gulbransen;986089]Your well trained eye can probably tell by the motion blur in the frame grab, right? Trust me, or not, my clipping issue - so far as I can tell - is not related to any shutter speed/techniques that I use.
QUOTE] Do I detect a hint of sarcasm here? ;-) I am sorry if I offended you. It was definately not intended! Actually, I did not even think as far as Allister did concerning the auto shutter possibly being the source of your exposure problem. I just wanted to make you aware of the fact that while using the shutter to control exposure is an excellent choice when shooting stills it gives some very obvious and nasty effects when shooting video. I noticed this on some of your shots on the video clip you linked to (with my well trained eye) and it was confirmed by the still of your view finder. Earlier this year I worked with some footage from Kongo shot by a stills fotographer who was new to video. He was great at composing his images but unfortunately he did not realise the difference between using the aperture and ND to controle exposure as opposed to shutter speed. The images looked like holiday movies. I hope this can be of some sort of help to you (or somebody else). :-) |
December 30th, 2008, 03:47 PM | #37 | |
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They did seem particularly interested in the 700 though, but their set of circumstances is particularly demanding so it would need to prove itself. |
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December 30th, 2008, 04:42 PM | #38 |
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RSPB have a highspeed Arri that'll do 150fps so until there's a video camera that'll do that they'll keep using it (I'm doing a Phantom HD shoot for them but that's even more pricey than shooting film!). But, just like everyone else they know the benefits of shooting tape - cost only being one of them.
Last time I spoke to Mark they were very keen to get something ASAP,just had demos of 2700 and pdw700 and as I said they were waiting on my 720 results from the PDW700 to help the decision - just taking longer to get the 720 update than I' hoped! Steve |
December 30th, 2008, 04:49 PM | #39 |
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Interesting. Sounds like they really want to bite the bullet now.
Any idea why the update is taking so long? A lot of guys in the US have already got their updates. |
December 30th, 2008, 05:10 PM | #40 |
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Apparently there's a queue and you wait until your number's called, but I can't believe there are that many that need doing, it's been available for about 2 months now.
Steve |
December 30th, 2008, 05:28 PM | #41 |
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If I can give my 2 cents on this really interresting thread :
- even if you assume the problem does not come from the auto-shutter, have you ever tried with fixed shutter ? What was the result ? - if you can't trust the monitor, the LCD, the viewfinder and the zebra... go for a rent of an oscilloscope. Astro have real good ones. Then you'll have the real brightness all over the frame, and be able to quantitize that. This is expensive, but I NEVER work without it when I can afford it. when you know how to use it, it will save you a lot of shoot. - take some time, same shot, to experiment every gamma curve. I'm sure you'll find the good one. Maybe one is not good for all shots, even if they are all in the sun during the same day. - EX3, or most of the "8 bits" camera will never have the same picture as 10 bits camera or some still camera with RAW files. You have to know that :) - the histogram on the EX1/3 is tricky. It is just giving the % brightness of the image. Black on the left, white on the right. When you go over 100IRE (I think it's 100), the last bar on the right start to increase. If your camera is set right, you should be able to go close to the last bar on the right, without touching it. Once again, an external oscilloscope will enable you to set the right brightness on your subject, without burning it. I hope this will give you some paths to walk by yourself. |
December 30th, 2008, 05:59 PM | #42 |
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I wouldn't trust that histogram at all because its resolution, as Alister pointed out, is not high enough. You cannot see what each RGB channel is doing.
I think that part of this is playing around with the camera in a wide variety of conditions to get to know it. I'm still going through 'getting to know its behavior' blues with my own EX3. I put it down to the finnickiness of a consumer/prosumer camera. The big cameras you can generally trust a lot more. Now if someone would just give me an excuse to get a 700... |
December 30th, 2008, 06:16 PM | #43 |
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The white clipping has been discussed in several threads earlier and there I found the resolution for my problems with ex3. Dont quite remember the name of the thread but the problem was solved - as far as I remember with a knee setting of 90 and a slope of 50.
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December 31st, 2008, 01:10 AM | #44 |
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Be careful that you are not seeing steps (banding) due to your LCD computer monitor or LCD TV screen. In my experience most LCD screens display a small amount of banding in gradients. If you have a CRT studio monitor or expensive LCD monitor then you shouldn't see this.
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December 31st, 2008, 02:59 AM | #45 | |
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