Ex1 picture

[Barry Uddstrom]

Hi Ian,

Think I have had a similar problem.

Where the shimmering is in the picture is the sun light reflecting back to the camera?
Is it the shiny part of the leaves that are shimmering could these parts be overexposed?

I have not had time to work out the different situations that this occurs but I'm sure its to do with the light reflections

Don't know if I'm of any help, just letting you know I have had what looks like a similar problem in 25P

Regards
Barry

[Ian Thomas]

yes thanks Barry

i think 1080i is the way to go it looks better if you do shoot 25p i think you must use a tripod because any movement is more visible in 25p

[Graeme Fullick]

Ian,

I know exactly what you are referring to - I had the same problem with 25P - and no longer use it for that reason. You should also look at your detail settings - changing these down to -10 or -20 will also help a lot. It is the sharpness of the EX1 - especially in 25P mode that causes the problem.

[Alister Chapman]

I doubt very much that it's a problem with the sharpness of the camera. Whether 25P or 50i. It's far more likely to be a monitoring issue. When you get a chance try to look at your EX pictures on a proper HD monitor, not a TV or Computer Screen. TV's have detail and sharpness enhancing circuits that tend to be set way too high and computer monitors very often run at inappropriate refresh rates and the conversion from HDSDi to DVI or the playback from the computer can also be questionable.

Blurring of shots when the camera moves is often simply a function of detail correction or sharpness controls. These use multiple frames to generate the enhancement signal. As the image moves the reference required to create the signals is lost and the detail enhancement drops, thus the picture softens. This applies to both the camera and domestic and consumer TV's. It tends to be more noticeable at 25P because a static 25P frame is higher resolution than 50i so you notice the drop more. The other thing to consider if shooting 25P with no shutter is that there will be much more blur due to the longer exposure (1/25 as opposed to 1/50 for 50i), so normal practice when shooting at 25P is to use a 1/50th shutter. Again when judging 25P motion it is VITAL that you use a monitor capable of correctly displaying 25P. Computer displays are notoriously bad at 25P as thier refresh rate is usually 60fps and 25 into 60 just doesn't go, the end result is juddering motion which isn't really there.

[Graeme Fullick]

Alister,

I agree 100% with everything you said - but the unfortunate thing is that the final destination for mine (and most others) footage is a TV - probably with all of the flaws that you described. Hence the need to "create a compatible picture" by softening detail and shooting with 50i becomes a necessary evil.

I know that the camera shoots wonderful 25P pictures - unfortunately we often don't see them because of the TV's that we view them on. Very few people look at movies on broadcast monitors - except of course us video editors!

[Craig Seeman]

I'll throw out some explanations that might help.

A 1920x1080 image in progressive is showing 1080 lines for each frame
A 1920x1080 image in interlace is showing 540 alternating lines for each field (2 fields to a frame).

If an object is only one line you may see "line twitter" (my guess it's what you're calling shimmer) if you're playing on an interlace monitor.

I suspect there may be some objects or edges in your progressive footage that are about one line so you're seeing twitter. If you're monitor were actually showing progressive you would not be seeing that. There are some "1080p" HDTVs that are not "progressive" when using some inputs. I was very careful when reading the specs when I bought my 46" 1080p HDTV to make sure all HD inputs were truly 1080p.

Specific to Graeme's comments, you can't make a generalization like that. While some 1080p monitors are "p" on only some inputs and some are all so it really depends on the method of delivery. Delivery might be Blu-ray, broadcast, file playing device and the output and tv input used, for example. In general, player with P source to an HDMI input of a "p" HDTV will properly show "p." Other inputs may not (depends on the HDTV).

maybe this will help too
1080p Facts - Home Theater Tip - What You Need to Know About Accessing 1080p Resolution on an HDTV

This is specific to Blu-ray
Blu-ray Disc - Wikipedia, the free encyclopedia
but keep in mind file player (and that includes computers) don't have those restrictions.

Note that Doug Jensen of VortexMedia says he shoots 1080p30 and down converts (see his EX training DVDs) and those 1080p sources to a Standard Def DVD played back on an SD or HDTV look fine (no line twitter).

[Alister Chapman]

I shoot all my own material as Progressive. About the only time I shoot interlace is when shooting airshows where the client specifies interlace, even that looks like it will change to P next year.

Interlace really is a hangover from the past where there simply wasn't the bandwidth to broadcast full resolution (SD) progressive frames, so the compromise that is interlace was developed to split the frame into 2 half's. These days with most display technologies centering around progressive scanning I'm not convinced that interlace is the way to shoot. Obviously if your client insists on interlace then that's what you must deliver.

I supply hundreds of hours of footage to broadcasters, museums and corporate production companies around the world. I have been shooting progressive since 2004. Often I deliver the material recorded as interlace, but containing progressive images. Not once has that caused me a problem. As I write this I am converting some 1920x1080 25P footage to 1920x1080 60i for delivery to NBC. If I had shot 50i that conversion would be very difficult to do and to make look good. It is so much easier to start of with P and convert to either P or I. If you start with I then you immediately have a resolution drop if you shoot with a video camera because the fields are created by using overlapping line pairs from the sensor to prevent twitter an aliasing. Converting that already resolution compromised footage to progressive will almost certainly result in a further resolution drop as you will need to do some form of de-interlace procedure. On a big screen that drop in resolution is very noticeable. Converting from P to I on the other hand has none of these issues and frame rate conversions from P to P are easy.

More and more broadcasters are now insisting on progressive delivery of HD material, especially for documentary, drama and other high end productions. Often this is because international distribution of progressive is so much easier and the quality better. Sure 25P is not ideal, 50P would be better. But working with progressive material is so much easier than working with interlace.