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Checking Log exposure with the Hi and Low Key Function on the PXW-FS7, PMW-F5 and PMW-F55

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A great function that allows you to check the extreme ends of your log exposure in the CineEI mode is the Hi/Low Key function. It has to be assigned to a button before you can use it, but it provides a very fast way to check what is really going on in your highlights and shadows. You’ll find all you need to know about High and Low key here.

Scene Files and Luts

Low Light Picture Profile for EX1/EX3

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I get asked a lot about settings for shooting in low light with the EX1 and EX3. To be honest there is not much that will make a big difference that can be done, beyond adding in camera gain. There are a few tweaks you can make to the picture profiles that will help minimise noise levels and give a slightly brighter picture without resorting to overall gain and I’ll go through those here.

Gamma: By using a brighter or higher gain gamma curve you can get a slightly brighter image without an across the board gain increase. Do however consider though that gamma does add gain so a brighter gamma curve has more gain and thus more noise than a darker gamma curve. Where you light range is limited or controlled then I recommend using Standard Gamma 2 with the black gamma set to +40. Raising the black gamma helps lift shadow and dark areas of the image. For scenes with bright highlights then it’s useful to have some extra dynamic range and in this case I would choose cinegamma 4, again with the black gamma raised, this time to +50.

If you are happy with turning detail off altogether then this may be a wise choice as it will prevent any noise from being enhanced. If not in order to keep the appearance of noise to a minimum I would decrease the detail level to -10. As we are shooting in low light then I will assume there are a lot of dark areas in the image. To keep noise less visible in low contrast areas I would set the crisping to +50.  This will slightly soften the image but help control noise.

There are two principle forms of noise, chroma noise and luma noise. There’s not much we can do about luma noise other than controlling detail enhancement as above, but if we reduce the image colour saturation we can reduce the chroma noise. Better still using the low key sat function we can just reduce the chroma (colour) level in low key parts of the shot. So for my low light profile I would set Low Key Sat to somewhere around -50.

So by changing the gamma we can increase the sensitivity a little, turning off the detail correction or using crispening we can ensure that the visibility of any noise is as minimised and the Low Key Sat function will keep the noise to a manageable level.

These setting won’t turn your EX1 or EX3 into a mega low light monster, but they will give a small boost to the low light performance before you have to resort to adding gain. Talking of gain, do make sure you read this to understand what gain is doing.

EX1/EX3 Picture Profile suggestions for low light:

Gamma Standard 2, Black Gamma +40  OR Cinegamma 4, Black Gamma +50

Detail OFF or Detail Level -10, Crispening +50

Low Key Sat -50

Black level -3 (restores black to zero)

 

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Low Cost 2/3? HD Lenses.

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OK, here’s my take on the situation.

If money is no problem then the safest bet is to purchase a good quality HD lens, expect to spend at least £8k.

If you budget is restricted then the situation is much less clear. There are now several low cost 2/3? HD lenses designed for cameras such as the Panasonic HPX500. In my opinion these lenses are just not worth the money. They might be cheap (£4k ish) but the one’s I’ve played with have been pretty grim, suffering from lots of CA and soft corners.

If your on a tight budget the best thing you can do is take your camera to a good dealer and go through their second hand lenses, trying them on the camera. Check for resolution (use a chart), corner softness, CA and contrast. I did this and ended up with a Canon 16x8x2 IF lens. I found that lenses with lower zoom ratios tended to be better than those with higher ratios. I’m really pleased with my lens and when compared to the latest HD equivalents I can not tell the difference in real world use. It certainly outperforms all the budget HD lenses I’ve tried.

One interesting thing that I have discovered in my research into this subject is that Contrast is what makes the biggest difference in lens performance, not simply resolution as one might expect. Visually the next thing you notice is CA. This is a tough one as when you increase the resolution or sharpness of a lens you also tend to increase the CA.

Until lens manufacturers start to release MTF curves for their lenses the only thing we have as buyers to go on is the advertising blurb. It’s easy for a manufacturer to claim improved performance or new glass or other technology, but without accurate MTF curves it’s all pretty meaningless. You would only need the tiniest resolution improvement to be able to claim that you new HD lens range is sharper than your SD range, it could just be a fraction of a percent difference.