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-   -   PD150 / PD170 Depth of Field (https://www.dvinfo.net/forum/sony-vx2100-pd170-pdx10-companion/55385-pd150-pd170-depth-field.html)

Emre Ramadan December 2nd, 2005 10:46 AM

PD150 / PD170 Depth of Field
 
Hi,

I'm quite new to this site, I'm looking at the possibility of buying a PD150 / PD170 as my first camera for film-making. One question I have regarding this is its depth of field capabilities. I could not find a thread on this (though there are quite a few to look at!!) so I'm sure there is one.

Would an adapter be needed to obtain shallow dof results?

Thanks.

Don Bloom December 2nd, 2005 11:00 AM

DOF is determined by a number of things.
Shutter speed, f/stop, ND filter, distance to subject, using a WA lens attachment or not, lighting on the subject.

To get a shallow DOF you use the widest f/stop and highest shutter speed possible to get the proper exposure-use the ND filter if needed to open up the iris-get in as close as possible to the subject and never use any auto settings-exposure or focus as this will work against you in most cases. I use the 150s for some of my work and it can certainly be done but it takes a bit more planning to achieve shallow DOF than when I use my full size camera with a professional type lens. It can be done though-check out MArk and Trisha Von Lankens work to see for yourself, they use a DSR250 and a PD150 and achieve very nice shallow DOF with them.
HTHs
Don

Mike Rehmus December 2nd, 2005 11:42 AM

The depth of field of any given lens focal length/CCD size combination will be the same at a specific aperature.

A DSR-250 won't do any better than a PD-150/170 at this.

A 1/2" or 2/3" can generate a shallower DOF at the same aperature (say f-2) than a PD-150 because of their larger CCDs (assuming the same field of view).

So if you run the PD-170, say, at a wide-open aperature, in general, it isn't going to get any better with add-on optical devices (the one exception would be if you add a telephoto adapter and use it to generate a longer focal length than the camera's longest setting.).

I shot a scene from a movie on Thursday with a PD-150 and instantly regretted not lugging the DSR-300 along. Instead of achieving a shallow enough DOF, we had to control the lighting to make the foreground sort of go out of focus.

Whew, I think I covered all the bases.

Joshua Provost December 2nd, 2005 01:36 PM

The PD150/170 have 1/3" CCD's, so they will have similar depth of field to the Panasonic DVX100, Canon XL2, and all other 1/3" cams. It's roughly the equivilant of 8mm film depth of field. Not great for shallow depth of field, but manageable within a certain range.

Marcus Marchesseault December 2nd, 2005 06:17 PM

The PD/VX series of sony cameras have a very broad depth of field. This is caused by the small CCDs. All image capturing devices (video, still, film) with a small imager will have a broad depth of field. There are very few video cameras that will have anything approaching the DOF seen in 35mm cameras. To get the type of DOF that you see in movies and on TV shows shot in 35mm, you need a 35mm lens adapter. Go to the "Alternate Imaging Methods" section in this forum. You will find everything you need to get started there.

Using telephoto to get a narrow DOF will give you a very narrow viewing range (like looking through a tube) which is usually not acceptable. To have a wide viewing range and narrow DOF, you must effectively increase the imager size. This is the function of the 35mm adapters. They focus the 35mm lense on a ground glass screen and your video camera picks up this image. In effect, the video camera lens is doing nothing and the 35mm lens is doing all the focusing on the larger 35mm "screen".

Emre Ramadan December 5th, 2005 08:44 AM

All,

Thanks very much for your help, much appreciated.


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