maximising depth of field? limit of dslrs for video

[Patrick Janka]

The guy has plenty of knowledge and experience to draw from. Check out his website and watch his vids. This isn't some knucklehead with a Sony Handycam spouting off.

[Jeremy Dallek]

Originally Posted by Jim Giberti

I didn't watch the tute but if that's what it says then it's not accurate.

Originally Posted by Bruce Foreman

Because we have "everybody and his brother" making "tutorials" whether or not they have the knowledge/experience to draw from.

You may want to watch it before discrediting the information that you think may be in it from second hand hearsay. The information in the video is accurate. The statement "Sensor size does not change the DOF" is also accurate.
If you watch the video he explains as I have that all else staying the same, it only changes the FRAMING(or Crop). You are correct though that to achieve the same DOF with the same FRAMING would be more of a challenge with a smaller sensor due to the changes needed in lens focal length/aperture. Changing the distance can also compensate, but then you are changing the perspective, which would not reproduce an identical image.

What would be the solution to all this? An converter/adapter that fits between the lens and the body (similar to the teleconverters that are available) that optically compensates for the crop size of the sensor, adjusting the image circle of the lens to fall on the sensor in the same proportions as the original comparative example. This would also have the positive effect of an increase in light density equal to the factor of the converter.
Example, GH2 with 50mm FD mount lens and M4/3 adapter, 2x crop sensor. Create a micro 4/3 adapter with optics inside that would make it a .5x converter, Now you have the same framing as a full frame sensor because you are using the full image circle of the lens instead of only the center half, and you have also gained a stop of light (2x factor increase in light).
From what I remember reading, this is very possible, but was patented by a company (Kodak I believe) and therefore Panasonic/Olympus or third party manufacturers are blocked from producing it.

[Jim Giberti]

Originally Posted by Patrick Janka

The guy has plenty of knowledge and experience to draw from. Check out his website and watch his vids. This isn't some knucklehead with a Sony Handycam spouting off.

I would never call him names. I just said that claiming that sensor size doesn't impact DOF is inaccurate, and stated why in my experience. Lot's of things, foreground background proximity, iris, focal length and yes sensor size all directly impact DOF.

It's just physics, not a debate. Like I said, I didn't have time to watch the tute but here's the simple point. In order to get anything close to shallow DOF on say an "old school" DV camera like the XL1 or XL2 you would need to shoot very long - 300, 400mm or more, and have your foreground and background very separated.

Even then, in all but the largest interiors it just won't work practically. In other words, in the only sense that matters - practical production, the smaller the sensor, as we shoot them, the more difficult it is to get shallow DOF with a common lens in a common setup.

So while theoretically he may make sense, practically, if there were no difference, there never would have been Letus and P&S Mini 35s, and the 5D revolution wouldn't have meant what it did.

That's my opinion with no ill will toward the OP or person who made the tute.

[William Hohauser]

All I can do to add to this interesting discussion is that on the GH3 (and probably on the GH2), there is no functional difference in DOF between shooting HD, shooting EX. Tele or shooting a full frame still with the same lens.