Good image quality on a sunny day (ND Filter)

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WindSandStars

Member
I will shoot a docu in very bright and sunny environment.

I made some tests with the internal 1/8 ND Filter setting and an aperture of F5,6 on a sunny day in my home area. I did the same shoot with the aperture set to F16 without ND-Filter. I caputered the footage with Avid Xpress Pro.

I saw no difference in the image quality between this two settings.

What is the correct way to go for a good image quality on a very sunny day: Is it important to aim for a certain aperture like F4,0 with a ND-Filter? Do you encounter a quality difference between the internal ND-Filter and an external ND Filter? I use a Crossziel 4x4 mattebox. Do I need no Filter as long as I can go up to F16 without a loss in image quality? Does the internal ND-Filter lower the image quality compared to F16?

How do you capture a nice blue sky on a sunny day?
 
Re: Good image quality on a sunny day (ND Filter)

I'm no expert, but I think usually ND filters are used in bright environments so that you can shoot at a lower F-stop (i.e. 5.6) and reduce your depth of field (have a nice soft background image and sharp foreground image). I think there are sometimes other advantages to shooting low f-stop as well, but I can't recall them right now. Some lenses have a "sweet-spot" (for sharpness) at certain f-stop settings, but I haven't seen any data on this for the DVX's Leica lens.

To get a nice blue sky, there are several options:

1. Just expose the sky properly (with or without ND filters) -- make sure you have no "zebra stripes" on the sky.

2. If you have a face (or some darker object) in the foreground, add light to that dark object so that it's brightness is close to the sky's brightness. That way both will be properly exposed & have nice colors.

3. If you have dark objects in part of frame, and bright sky in other part of frame, you can use ND-grad filter and rotate it appropriately so that the "grey" part of filter reduces the light from the sky, and the "clear" part of the filter is over the dark object. This will bring the sky and the object to similar light levels.

Hope this helps - have fun!
 
Re: Good image quality on a sunny day (ND Filter)

One of the advantages with a very sunny day is that the ground and sky can be exposed quite nicely. A dull day will have the opposite effect, glarey sky and dark ground, makes for horrible shooting conditions.

It also depends on what you are shooting. If you are shooting a person, use a reflector and have the sun to one side, not in the person's eyes and not behind him/her because you will have a hard time with proper exposure.

Go to my post in the screenshots area "Water's Edge Part 2" and look at the first file, about four or five shots into that film is a shot of a beautiful blue sky with flowers, etc., all perfectly exposed and looking almost like technicolor...

Generally, you will get a sharper image if you stay around the f4-5.6 area. You will also get a shallower depth of field than f16 which will pretty much have everything in focus...if this is a consideration for you.

These issues of sharpness are less of a concern if your final output is going to be DVD but if you are going to film, then you must be a lot more critical in how you shoot because on the big screen everything will be glaringly obvious.
 
Re: Good image quality on a sunny day (ND Filter)

I use a revolving polarizer to increase significantly the color saturation of a sunny day and obtain a nice dark blue sky too.
 
Re: Good image quality on a sunny day (ND Filter)

The lower image quality with the higher F-number is mainly due to diffraction. This effect lowers resolution and small area contrast. A perfect external ND filter can even be better because the light scattering around between the lens elements is lower resulting in lower global image flare.
 
Re: Good image quality on a sunny day (ND Filter)

Diffraction doesn't usually become an issue until you're into really small apertures thought, right? I haven't seen any diffraction issues until you get down to like f/32, maybe f/22... and the DVX can't go that tiny, it stops at f/16. So is diffraction an issue with the DVX? I haven't tested for it, but it'd be good to know if we should be shying away from f/16, etc.
 
Re: Good image quality on a sunny day (ND Filter)

Barry, F-16 is known to create visible resolution loss with 1/3"chips. See e.g. http://www.bealecorner.com/trv900/dof.html. I don't own DVX but I wonder what happens with the DVX aperture in auto mode ( shutter 1/60) and the light goes up, beyond the the limits of f-16 and internal ND. VX2K closes down to even f32 (with strong resolution lowering) unless the autoshutter is set "off " in the custom settings.
 
TRe: Good image quality on a sunny day (ND Filter)

TRe: Good image quality on a sunny day (ND Filter)

Thank you for your information. Your hints are very useful.

Concerning diffraction I did not see any difference in image quality between ND 1/8 – F 5,6 and F16 without ND Filter. I did expect a better image quality with ND Filers. I will do some further testing with external Tiffen 4x4 Filters ND and Polarizer Filters.

I own a Panasonic SDX 900 with a HD Zoom Lens as well as the PSTechnik Digi35 Adaptor with Zeiss Prime lenses. But for the current project I will use the DVX 100 because of size and weight. The DVX holds up just fine.

With my Panny SDX 900 I use to white balance with warm color charts and take advantage of the powerful color settings of the camera. Do you have experience with the DVX and white balance with warm colors? Does it make any difference?

For this project I will use a DVX 100 but not a DVX 100A. I guess I know the difference between this two cameras. Do you think that the 6db gain in progressive mode of the DVX 100A is an issue?. For my current project in another country I don’t know what lightening problems I will be confronted with. I carry four Dedolights with me which can be connected to almost everything like a car battery. Some shoots will be in houses. Is the DVX 100A a big advantage?
 
Re: Good image quality on a sunny day (ND Filter)

[quote author=andre link=board=Events;num=1089925524;start=0#6 date=07/16/04 at 11:48:55]Barry, F-16 is known to create visible resolution loss with 1/3"chips. See e.g. http://www.bealecorner.com/trv900/dof.html. [/quote]

Hmmm.  I'd read that article years ago, but I didn't remember him being so conservative with the f-stops (saying to be cautious even when using f/11). Yet there it is.

With the XL1, the shots at f/32 were just unacceptably soft, and Canon attributes it to diffraction, and it seems like a reasonable assertion.  f/16 (the smallest aperture on the DVX) I've never noticed any sort of resolution loss, but then again I haven't tested for it.  But f/16 is two full stops more open than f/32.  I'd be surprised if you had to go all the way to f/11 to ensure sharpness, but hey -- that's what resolution charts are for.  I'll add that to my list of things to try here some day (unless someone else wants to take it up?  Shoot a res chart at f/16, then swap in the ND filter and shoot it again at f/5.6, and compare the results?)

I wonder what this portends for the XL2 then -- that article says that with 1/4" CCD's, you should avoid anything more stopped-down than about f/5.6! When shooting 4:3, the XL2 uses a patch of the CCD that's no bigger than 1/4". Could make for some soft footage in daytime exteriors!
 
Re: Good image quality on a sunny day (ND Filter)

WindsandStars,

6 db of gain may be an issue with both DVX100 and DVX100A for dark scenes.

I know of two ways to reduce the chroma noise, but there may be more.
1-if possible, stay with outdoor and indoor white balance presets, it is always quiter.
2-normal color matrix is quiter than cinelike. To compensate, i use color saturation +4 and chroma phase +2 or +3.
3-if you use the DVX100A, avoid cinelikeD, it is a normal cinelike tweaked with gain and highlight compression, a sort of "illusion" of a broader dynamic range, and it creates a lot more noise in shadows.

hope it helps
 
Re: Good image quality on a sunny day (ND Filter)

Thanks all of you!

Now I am well prepared to go to Albany and bring this thing into the box... ;D
 
Re: Good image quality on a sunny day (ND Filter)

...well from an unscientific standpoint. the sharpest images ive ever taken with the DVX straight from the cam were when I was @ f/16..

..i was also using the anamorphic adaptor at the time and distance to subject was about 3-4 inches from the glass..

detail, and color rendition were all superb. i really didnt notice any chromatic issues, or anything i would deem the image flawed by.
 
Re: Good image quality on a sunny day (ND Filter)

I did a lot of testing meanwhile...

If you own a SDX 900 you are always close to say: Why not carry this puppet with you... it is just a little overweight... Two more cases to carry... best SD Camera on the planet… three people to carry the luggage…

But I stick to the DVX 100 on this project... small and mobile on the set… not so frightened to the protagonists (children) in front of the camera…

I tested ND Filters and now I am very familiar with the camera and I am able to produce nice footage… I use internal and external ND Filter and polarizer almost all the time… I did some nice rag shoots with a shallow depth of field… Looks like 16 mm… Much better than I expected… F2.8 (due to the internal ND Filter) allows a shallow depth of field which is not possible at F16…

I am wondering: I switch to ND Filter 1/8 all the time at bright lightening conditions… sometimes the camera says “ND-Filter off”… but still I can open the aperture more than if I switch the ND Filter off… So even if it says ND Filter does not work still there is a difference… Did someone test this with the ND Filter set to 1/8 even if it says at some light conditions “ND-Filter off”?

I red the article of Adam Wilt (www.adamwilt.com) on the DVX 100… He says that the DVX 100A produces more luminance… I saw the pictures he made… I think the differences in the pictures are significant… Is that true that the DVX 100A has more luminance?
 
Re: Good image quality on a sunny day (ND Filter)

I had a DVX100 and now i have the DVX100A.

I never saw any luminance difference.
The improvements i saw are the stronger and more detailed colors, and the slightly improved dynamic range.
It also has CinelikeD, which boost the dynamic range electronically by adding some gain in the shadows and compressing highlights a little more. So it gives the illusion of a broader dynamic range.

My DVX100 peaked highlights at 110 ire, and my DVX100A also peaks highlights at 110 ire. So both need luma compression in post. ( big priecy shoulder cams also need highlight compression in post anyway)
It's very normal for video.
 
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