DSLRs: am I just being paranoid?

[Corey Graham]

Originally Posted by Bill Edmunds

A real amateur question here: do you put on a protective UV filter when you use a DSLR? Whenever I've looked at photogs, they never seem to use one.

Also, I seem to recall a few people mentioning an add-on for traditional video cameras that lend a shallower DOF? True?

I've abandoned UV filters, as they're really not as important as vendors would have you believe. The big push is that they help protect the front element of the lens, but in reality they don't make that much difference. Their "real" function is to reduce UV haze, but I've never noticed any difference. And in theory, anything you put in front of your lens is modifying the original image.

DOF adapters aren't worth it either, IMO. They're a hassle to use, and usually affect image quality dramatically.

[Chris Harding]

Back to George's question

Sorry if this is going a bit off topic on the 720/1080 but I posted on the Sony Vegas forum and it seems it's more what the NLE can handle rather than the image size that you are rendering down to SD!!

The older NLE's seem to struggle with resizing but most are coming up to speed so the general consensus seems to be it doesn't matter whether you shoot in 1080 i or p or at 720 p only. Any good NLE should handle the downsizing adequately. Admittedly I shoot in 1080i cos I'm shooting documentary style and it seems that most DSLR's only shoot 720P which is understandable as the last thing you need is for your DSLR footage to look like video!! If you wanted that you would use a video camera.

I'm not sure if any DSLR's do shoot at 1080 but to get the "look" I would be biased towards 720 anyway. Even with my "old fashioned" cameras I still set my scene profiles to be more "cinelike" and the result is good.

Chris

[Travis Cossel]

Originally Posted by Bill Edmunds

A real amateur question here: do you put on a protective UV filter when you use a DSLR? Whenever I've looked at photogs, they never seem to use one.

Also, I seem to recall a few people mentioning an add-on for traditional video cameras that lend a shallower DOF? True?

We no longer use UV filters as we don't see the benefit in putting a cheap piece of glass in front of an expensive piece of glass .. as in, we don't want to lose the benefit of our good glass by putting mediocre glass in front of it. d;-) Plus, in 6 or 7 years of using UV filters we've never had one 'save' a lens. It's possible one could, but just not worth it for us.

[Johannes Soetandi]

I notice that there's more ghost flare when I use UV filter. I tend to leave it off my cheaper lenses.

[Nicholas de Kock]

I use UV filters, it's my experience that cutting between a lens with a UV filter and without gives different results in direct sunlight when is comes to colour saturation. I've also scratched a $1300 lens that didn't have a filter which could have been easily avoided. As for "pro's" not using them? Many pro's do, every man has his preference. If you have great insurance I guess you don't have to worry. Personally I find it easier to clean the UV filter over my expensive glass.

"Video cameras are sensitive to both visible light and ultra violet (UV) light. UV is invisible to humans but it can create a blue tinge and/or washed-out effect on video, especially outside. A UV filter removes UV light while leaving visible light intact. UV filters are also commonly used as a protective filter for the lens." Media College

[Chris Harding]

Final answer about resizing for George!!!

The technically "correct" method is :

A reasonable algorithm to rescale 1080i60 to 480i60 is to first use a frame-rate doubling deinterlacer to obtain 1080p60, rescale this to 480p60 with a high quality anti-aliased scaling algorithm and then weave the resulting frames back to interlaced 480i60.

I see this as an incentive to shoot in 1080 50P for you!! Sadly the HMC's only shoot 1080 25P in a 50i wrapper so the closest I can get to double frame rate is shoot in 720 50P (which I can do) However even shooting interlaced I find that Sony Vegas 10 does a way better job of the resize than earlier versions so it seems like it's OK to shoot interlaced BUT get the latest NLE version that has the best algorithms.

I suspect because DSLR's usually shoot 720 and progressive, they will more than likely do the best resizing job when an SD DVD is needed

Chris

[George Kilroy]

Chris I don't know if I'm miss-reading your response, or I didn't make my knowledge gaps in the subject clear.

I'm not shooting with DSLRs; I do have one but as of yet I've not used it for paid work. I shoot with a traditional (let's not call it a proper) video camera, JVC HM700 so it's no slouch. The native CCD is 720p but it will record also at 1080x1440 50i and 1080x1920 50i or 25p as a 35mb MP4 or Quicktime .mov using the Sony EX codec, the same as the EX1 & 3, and I edit with CS4. I do all the encoding in CS4, either Media Encoder or Encore. I have read elsewhere and can understand (to a degree) the convoluted way to get the 'best' down-scaling but due to the time involved my work pattern does not warrant that amount of time spent. I deliver 90 minute wedding videos plus highlights and encoding is the frustratingly long part as it is.

I think my frustration is that the final DVD doesn't carry through the big quality increase I expected to be able to offer above that which I use to produce from my previous system using a Pana-DV200 full size DV tape camera. That's why after a year of shooting HD and delivering SD I'm thinking that I need to deliver on HD media, even though not one of my customers has asked for it, or plumps for it when offered.

I note elsewhere that you changed to HD to be able to deliver true 16:9 widescreen, that was exactly my motivation.

[Michael Simons]

Originally Posted by Bill Edmunds

A real amateur question here: do you put on a protective UV filter when you use a DSLR? Whenever I've looked at photogs, they never seem to use one.

Also, I seem to recall a few people mentioning an add-on for traditional video cameras that lend a shallower DOF? True?

Photographers have told me they don't want to inhibit the results of a $1,500 lens with a $70 filter. They use the sun-shade to protect their lens against scratches.

[Chris Harding]

Hi George

Yes I know you are shooting with the JVC (as you say no longer a real video camera..but for me it still is)

I was under the impression that you wanted to know (as I do too) if shooting 720 as opposed to 1080 does give a better result. I'm talking about edit and render not all these weird and wonderful multi-render processes and I wanted to know why????

The result above was the one I got BUT no-one has yet said "Shoot at 720, it will give you a better SD DVD.

I too haven't the time to go thru all these processes!!!!

We might actually get a direct answer from someone one day!!! Got a wedding in the morning so I will shoot it in 1080 50i as normal unless advised otherwise but I do like the idea of 720 50P (double frame rate)

Chris

[Jeff Harper]

UV filters hurt nothing, I'm sure. The glass is so close to the lens it really can make little difference if it's a quality filter.

It is much easier to remove a filter and clean it then to clean a lens, and when I'm done cleaning a filter I can hold it up to the light and see if it is really clean, can't do that with a lens on the camera.

I handle my lenses in the field, and sometime change them, more than once. I have got finger prints on them plenty of times. I have been working with ethnic clients who use grease in their hair, and I've gotten that grease on my hands, and being in park I'm screwed, everything I touch has the potential to get a greasy fingerpring on it.

Fumbling around at dusk with tired clients and we're all trying to go home and I have to change lenses one more time is when things happen. Gunk does get on the lens, it's almost unavoidable at times. UV filters are easier to clean and cheaper to replace than a lens.

[George Kilroy]

Chris, the person I know who convinced me to go along the JVC route only ever shoots 720p,and keeps things Progressive all the way and will never shoot any other way, but my personal experience has been that 720p edited in a CS4 Progressive project and encoded as a Progressive MPEG2 gives me a less than satisfactory DVD; I've had customers complain about flicker whereas the 1080i edited and MPEG'd as lower field interlaced gives a more widely compatible DVD. I can't explain why and I know it appears to go against all the perceived wisdom, though a google search has shown me I'm not alone with this.

As for the double frame rate, I'd don't see the advantage other than for slomo, as the final output is going to be 25fps, again my lack of technical understanding may be missing something.

[Jeff Harper]

720p converterted to SD for DVD should have no flicker. The problem is with the operator or NLE or the camera, not the intended workflow.

Unless I"m mistaken, there can be no flicker if you are keeping it progressive from beginning to end

At some step in your workflow something is wrong. What you are talking about sounds much like deinterlace flicker, or whatever, and should not be happening.

[George Kilroy]

I know Jeff and I've had this conversation over and over, but I have been unable to identify the fall down in the workflow, and I cannot dispute (at least with myself) the evidence of my eyes. It's difficult to replicate the problem other than watching it on a DVD as when the progressive workflow terminates in a computer destined file there is no flicker. I shoot 720P for output to Flashmovie no problem, but if I encode the same work as a Progressive MPEG and burn that to a DVD it flickers.

Anyway I don't want to divert this conversation into an area that I've had many discussions about in other threads.

[Jeff Harper]

Is your DVD authoring program re-encoding the file from your NLE?

1. Verify that the footage is progressive to begin with. If you know that is true, fine.

2. Verify the footage coming out of your NLE is progressive. You must be sure of this.

3. If the above is true, then your DVD program is the culprit plain and simple. You need to change the properties in your DVD authoring program, or if necessary change programs, I don't know what you use. In DVDA you must specify the footage is progressive or it will re-encode it.

I guess it could in theory be your DVD player? Or TV? But you said it happens on your customers also?

[Chris Harding]

Hi George
I was just about to say, ask Jeff!! AFAIK most DVD players don't like Progressive DVD's and some even refuse to play them and I was pretty sure that Jeff had an issue with that but I might be wrong!!

I shoot interlaced but Sony Vegas will de-interlace the footage for you before rendering so there is no nasty combs from the interlacing..so you are in fact editing progressive footage. (I actually de-interlace before importing) ..once the edit is complete it's then rendered out to a PAL DVD with interlacing applied and lower field first.

Most NLE's will strip the interlacing first and then interlace again during the render ..if you shoot progressive then the NLE leaves it alone but still interlaces the SD MPEG2 file. I have always done it that way anyway.

As said before not many DVD players can handle a progressive DVD and my default (PAL DVD PRESET) shows 720x576 16:9 aspect lower field first, so it's definately interlaced again.

Chris