View Full Version : HMC-40 and built-in neutral density


Brian Tori
November 1st, 2011, 01:00 PM
I know the 40 has the auto ND feature which kicks in automatically. My question is, is there enough ND to deal with full sunlight when shooting 24p at 1/48th? I've read that the iris only closes to f11 and after that it closes entirely. Some are complaining that there is not enough ND to keep highlights under control in really bright conditions. For those that own the camera are you having trouble in this area?

Graham Hickling
November 1st, 2011, 10:55 PM
If you want to mimic a "180" shutter - i.e stay fixed at 1/48, then you will almost certainly have problems unless you add an extra ND filter on the front.

I usually shoot 720p60 at 1/60th, and white signs and t-shirts blow out commonly on a bright day.

Edit: I see you are from Michigan. I have to say I had no problems with the camera when I lived in East Lansing - it was almost always cloudy ;)

Tom Hardwick
November 2nd, 2011, 04:27 AM
The AG-HMC40 includes three 1/4.1-inch CMOS image sensors so you really don't want to be shooting at any aperture smaller than f/4.5. If you place an SD card in the middle of a normal A4 sheet of paper that will give you an idea of how very tiny the 'less than quarter inch' chips are alongside the APSc DSLR chip in the Canon 7D say, whose chip is the size of the sheet of paper.

So by all means use extra ND, remembering that using chips this small means keeping the iris wide for sharp pictures. The Panasonic TM900 has 3MOS chips of the same size and this camera keeps the lens fully open as you shoot, introducing the vary-ND to control exposure. Only as a last resort does it start to actually stop the lens down.

Another couple of points. You may find that adding external ND doesn't in fact stop the highlights being blown. ND only absorbs light, it'll do nothing for the contrast ratio of the cam's overall processing.

And do get the best multi-coated ND you can find. For starters they will be your new front element, and secondly adding filters will mean the hood's efficiency is reduced.

tom.

Bob Diaz
November 2nd, 2011, 10:40 AM
For 1/48 of a second and outdoors, you'll want an ND 0.9 or an ND 1.2 (the 1.2 gives you a bit more room for to open the iris).

Be careful when picking the ND filter the lower cost NDs will cause a color shift that the camera will not correct for.


Bob Diaz

Brian Tori
November 2nd, 2011, 04:54 PM
It's surprising that this camera doesn't offer enough ND to work with full sun. I used to own a Panasonic SD100 which also had built-in ND and it had enough to work with bright outdoor conditions. I was considering this camera but now that it will require additional ND filters I'm going to reconsider.

Tom Hardwick
November 3rd, 2011, 04:25 AM
Brian - it may well not require additional, external ND in bright sun. Mind you, without it it may simply assume that you'll be happy to let the camera shorten the shutter speed (as the TM900 always wants to do) and generally this isn't what filmmakers are happy to allow.

So extra ND isn't a unique requirement of this cam. In my view all cameras can benefit with greater ND, though of course switchable, internal three options (like the NX5) is the way to go. External filtration on anything with chips 1/3" and smaller is asking for trouble.

tom.