Looking for a lens option to provide a low DOF (F355L)

[Jonathan Ferber]

I've got addicted to the low depth of field that the EOS 5D provides such that I'd like to be able to rent a lens that caters specifically to this purpose. I'm just running a Canon Lens (HDGC KH13x4.5 KRS SY14) on a 355L and will be doing a series of close up interviews (head and shoulders) where I require the background to resemble the beauty of my 50mm prime F1.8 on the Canon 5D. If anybody out there has any recommendations into the glass that provides this look please let me know!

- Jonny

[Alister Chapman]

You have two options really.

One is to move the camera back away from the subject, then zoom in and use as much ND as you can to get the lens iris wide open. It doesn't matter what lens you use, DoF is governed by focal length, aperture and imager size, so simply swapping the lens won't change the DoF.

The other option is to use a 35mm adapter that allows you to use 35mm stills camera lenses by projecting the image from the 35mm lenses on to a spinning or vibrating ground glass screen. The screen is then filmed by the camera giving 35mm DoF. These adapters are not perfect and require careful setup and will always use a stop or more of light. For the F355 etc the choice if adapters is limited as you really need to use a relay lens. One example would be a Letus35 Ultimate with 1/2" relay lens, which cost in the region of $7,500 USD. On top of that you would need some good quality stills camera lenses.

[Jonathan Ferber]

Looks like my best option would be to invest in a lens that provides me with more of a telephoto so I could zoom in tighter while standing further away. Investing in cinema grade glass and adapters as nice as that would be probably isn't in my best interest haha. Thanks for your input though!

[Eelco Romeijn]

The Canon is able to record HD video. So, why don't you use the DSLR for recording these interviews?

[Jonathan Ferber]

Well I would personally, but our producer isn't convinced yet by the quality/operation of the EOS 5D for this particular production so I've been sent on a mission to replicate the look it produces with our available ENG equipment. After much experimenting through the week I've come to a pretty happy medium on how to achieve a similar feel, it's not exact but it's certainly a good start.

[Eelco Romeijn]

I can imagine his doubts Jonathan, maybe i would be careful in these situations too.

What if you shot the interview with both cams side by side? You could have the sound recorded safely on the XD and an additional image on the 5D.

I guess everyone on this forum would love to see stills from this set to compare the differences.

[Steve Phillipps]

I don't think we really need stills to compare the difference, the results would be obvious - the 5D would look a thousand times superior, after all it is a stills camera!
Where the XDCam would win is ergonomics and better motion handling, less artefacts and probably a better codec I'd guess.
Steve

[Alister Chapman]

Stills won't tell the full story. Oversampled video such as that from the 5D suffers from edge aliasing which is most pronounced in moving images where edges "twitter" and just don't look right. The 5D codec is actually pretty good, but the compromise of having an ultra high resolution sensor with no optical low pass filter lets the 5D and most other DSLR's down. The requirements from the sensor for stills and video are quite different. Perhaps one day, maybe soon, someone will work out a way to make it work without compromising one or the other function. Maybe with swing-in optical filters. Were certainly very close, but at the same time, a long way off from having excellent stills and great video from one camera.