Iris and Depth Of Field

This may be a broad question, but lets hear some opinions.

If you are shooting in relatively low light situations, I was taught to use GAIN as a LAST resort. First open up the iris all the way (Lower the F stop)

Heres my question, in low light, if you lower the Iris, you lose depth of field. On the PD170, is their a gain setting (3 or 6) that doesn't noticablly degrade the video?

So for fellow pd170 users, in low light, what setting do you toggle first, the iris, or the gain?


Also, what is the purpose of shooting at a shutter speed faster than 60?


John

[Tom Hardwick]

Electronic gain simply boosts the signal electronically, so it gets noisier (i.e. more grainy) as you apply more gain. Go first to maximum aperture unless you're using progressive scan to shoot panoramas, where the vignetting at apertures wider than f4 will be apparent. The camera gives much better results at f1.6 and odB than it does at f4 and +15dB (both give the same exposure). Go to +6dB though and it's hard to spot the noise.

Choose shutter speeds higher than 1/60th if you want each frame to exhibit less subject blur. This is generally not good for movies, but if you're shooting PS or want to analyse the 'golf swing' it's a boon.

tom.

Yeah, Generally, I prefer shooting 60i with a 1/30 shutter speed than 24p for Movies. (Just my opinion)

What is PS?

Also, please tell me if this is correct.
If you are filming a long concert that needs to be webcasted, size and quality are major issues (For the output of the file). So contrary to what many people deem the Progressive on the PD170 being "Useless" I disagree. It looks much better to shoot 15P and compress to 15frame WMA or REEL, vs shooting 60i and converting it to a 15frame compressed media. Agree or disagree?

[Ralph Morris]

Another use for the "useless" 15 fps progressive mode is in shooting for stills. At 900 stills per minute (NTSC) with the ability to control aperature and shutter speed, there will be some great pics.

Obviously they are not much good for making prints, but for inclusion as stills in a video, they are excellent.

[Tom Hardwick]

PS is progressive scan John. And yes, I agree that the PS mode is indeed good for the webcast situation you describe.

Ralph - spot on about using the cam in PS mode to shoot hundreds of stills. I have a photo album of 6" x 4" prints taken of swimmers and few people (if any) realise they're not taken by a ''proper'' camera. Thing is each print hits the sweet spot in the springboard dive, the breathing in the crawl, the peak of the action in the butterfly. Trying to get those with a conventional still camera is *painful*, yet with a PS Sony, it's easy-peasy.

Few still cameras have anywhere near the frame rate, they don't have 12x wide aperture zooms, they don't have two viewfinders or record stereo sound. For passport photos a 5 second burst will give the client over 60 images to choose from, much appreciated by the ladies who have lived the last 10 years with their awful direct-flash passport photo.

tom.

[Ralph Morris]

Hi Tom,

I believe it was you that put me on to the use of the 15 fps mode for capturing great stills - about a year ago.

I've used the technique to capture hundreds of photos for use in school class videos. The pictures are superior to anything I could have done with a still cam. With at least 80 kids to get into each slide show, I doubt that I could have captured enough good pictures without the Sony.

[Tom Hardwick]

I'm pleased to have the feedback Ralph. I've been banging on for years now about the way the TRV900 and VX/PD can be used as still cameras all day long. Choosing *the* moment in time from the timeline at your leisure is a lot easier than predicting the peak of the dive, jump, smile. So why was it deleted on the TRV950, Sony?

Try printing some PS frames out Ralph. Pull the frames into Photoshop for a image size ajustment, then auto levels and an unsharp mask tweak. As I say, they're hard to tell from 'real' phots - probably because that's just what they are.

tom.