Don't wanna ask this, but I have to.

O

odonnelly99

Active member
Argghhh...sorry.

I was talking with my friend yesterday, who owns a DVX100B, about whether or not I should buy a 35mm adapter for my HMC40. He scoffed at my question and boasted that he is able to get shallow depth of field on his dvx decently enough without an adapter. Prior to this, I was under the idea that you couldn't do this on a lower priced prosumer camera without buying an adapter.

So now I'm wondering, is it possible to get any shallow depth of field out of the HMC40? I'm trying to learn everything I can about aperture and f-stops and doogley dooks and all the other jargon that makes my head hurt. I just would like to know if this is possible or not, before I spend a year incorrectly attempting to do something that isn't even feasible in the first place.
 
The answer is yes, BUT....

If you zoom into telephoto and you have the aperture around F2.8 --> OPEN, the depth of field is minimal. The shot is a telephoto shot, NOT a wide angle shot. Also, you would need ND filters or a fast shutter speed to be able to get around F2.8 --> OPEN in full sunlight.


Bob Diaz
 
Thanks for the quick reply, Bob.

I understand the sunlight issue. But what about an interior shot with excellent lighting? Same idea or easier to get the shallow?
 
As Bob said, it requires zooming in all the way to exaggerate the depth. Which is a bit difficult indoors. Depends on the room. Certainly you don't need a 35mm adapter, it just opens up some options for you.
 
BobDiaz said:
The answer is yes, BUT....

If you zoom into telephoto and you have the aperture around F2.8 --> OPEN, the depth of field is minimal. The shot is a telephoto shot, NOT a wide angle shot. Also, you would need ND filters or a fast shutter speed to be able to get around F2.8 --> OPEN in full sunlight.


Bob Diaz
Click to expand...
This would be a great video tutorial for us Newbs. Is there one out there yet? Thanks bob
 
JoeJITSU said:
This would be a great video tutorial for us Newbs. Is there one out there yet? Thanks bob
Click to expand...

The video forum is a bit of a tutorial for everyone. I'm in the process of trying to put links to the best items of interest.

Quick Index:
http://www.dvxuser.com/V6/showthread.php?t=199242

The FAQ & Articles:
http://www.dvxuser.com/V6/showthread.php?t=199448

The second link needs people to write things. The school semester has started for me and I have a FULL load teaching. So, I won't have a lot of time to write things until late June.


Bob Diaz
 
As I understood it, the aperture ranges smaller than F 2.8 (or somewhere in that range) are not real on the AG-HMC-40. An aperture reading of say F 8.0 is in reality a larger F stop with an ND filter, is it not? This is to prevent diffraction which creeps in quite quickly on such a high pixel count small size sensor. Does anyone know how small the aperture can be made before we get a "simulated aperture" using ND filters?
 
Adam Wilt's review says: ......The iris uses a four-sided, diamond-shaped aperture from wide open to about f/2.8, then a graded ND filter slides up in front of it for effective apertures (as far as exposure is concerned) between f/2.8 and about “f/6.8”. Below “f/6.8”, the physical aperture appears to shrink down again to “f/11”, then it caps......

So I read that as saying that the minimum physical aperture is slightly below F.4
 
Pavel+ said:
As I understood it, the aperture ranges smaller than F 2.8 (or somewhere in that range) are not real on the AG-HMC-40. An aperture reading of say F 8.0 is in reality a larger F stop with an ND filter, is it not? This is to prevent diffraction which creeps in quite quickly on such a high pixel count small size sensor. Does anyone know how small the aperture can be made before we get a "simulated aperture" using ND filters?
Click to expand...

As you close the aperture beyond F2.8, the ND filter starts to slide into place; this continues to F6.3. After than, the ND is fully in place and the aperture closes down the rest of the way. This comes for a posting about the F-Stops and the ND filter.

The ND filter reduces the light by....
(2.8 x 2.8) / (6.4 x 6.4) = 7.84 / 40.96 = about 1/5.22 or about 19.1%

So the ND drops the light by a bit more than 2 F-Stops; roughly 2.38 F-Stops

Now, if F6.4 = F2.8 with maximum ND filter
F9.1 is really F4 with maximum ND
Click to expand...


Bob Diaz
 
Thanks! This is interesting stuff to know. Does, do you think, the use of apertures such as F8 or 11 degrade the image in any visible way ... or is it something not to worry about?
 
On an HMC40, it's pretty clean up to about f/10. At f/10 it starts losing resolution (going "soft"), and the further you go (f/11) the softer it gets. There's not a massive difference, but it does start happening, and in general on an HMC40 you want to keep the iris as open as you can possibly get it.
 
In general, when shooting outdoors, I like to use a polarizing filter. I believe it reduces the light by about 1 and 1/3 stops. A polarizing filter also helps to reduce reflections and can make some colors a deeper saturation.

ND filters can also reduce the light outdoors:

ND 0.3 = 1 F-Stop
ND 0.6 = 2 F-Stops
ND 0.9 = 3 F-Stops

I believe that in full sunlight with a 1/120 of a second exposure, the F-Stop should be F-11. This assumes no ND filters...


Bob Diaz
 
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