ND filter or iris in bright light?

[Jerry Winters]

I own the xf300 and need to do a lot of outdoor shooting where it is very bright. Zebra set to 100%. What iris / nd filter settings do you recommend?

Also, I noticed adjusting the shutter angle resulted in darker video but I have a hunch this is not the intent of this setting.

FYI, I know I have tons to learn so I'm trying to limit myself to one question per week.

Thanks in advance.

Jerry

[Robin Davies-Rollinson]

The choice of iris settings is up to you, but generally I like to keep the setting around f4 - f5.6 outdoors in good light, but it all depends on the subject and how much or little depth of field you need.
By switching in the various ND filters, you can see when you are getting near to your ideal aperture.
I also have set my normal base gain level to -6db, rather that 0db, which also helps in controlling exposure.
I don't use zebras at 100%, but usually at 90%, but that's entirely up to you.
Ultimately, just set the camera up outside and make tests - you're not paying for film stock or processing...

[Doug Jensen]

The XF300/305 only has 1/3" sensors, so to avoid soft images due to diffraction, I recommend that your target f-stop should be between f/2.8 and f/4. Personally, I would never use anything smaller than f/5.6 on these cameras or you will see reduced image quality.

Therefore, you need to choose whichever ND filter will allow you to keep your iris in the f/2.8 to f/4 range. Obviously the right filter to use at any given time will vary as lighting conditions change. There is no right or wrong ND filter to choose.

As for the right zebra settings to use, that totally depends on the paint settings you have on your camera, and what you are measuring with the zebras. I generally use 98% but you have to know WHAT part of the image you are measuring with the zebras. Do you want to see zebras appear on white? middle gray? faces? who's face? etc. Setting proper exposure is more complicated that just saying "use ____ zebra."

As for shutter speed, you should never adjust shutter speed to change the exposure. Yes, changing the shutter speed will change the exposure, but that should not be the reason you are changing the shutter speed. Set it once and leave it alone. A shutter speed that is too fast will result in a strobing effect that looks bad, and a shutter speed that is too slow will have excessive motion blur. There is a very narrow range of shutter speed on a video that looks "normal".

If you're having trouble understanding these basic concepts, you may want to consider my XF305/300 training DVD. Even though they issues are not unique to the XF300/305, I do my best to explain them and recommend specific settings in the DVD.

Mastering the Canon XF305/300 Camcorders training DVD

[Jerry Winters]

Robin, thanks for the response. I haven't tried the -6 gain. I'll give it a try.

Doug, I have your DVDs. They're great! I have been trying to stay below f4 per your DVD. Shutter is set at 180deg.

I have not done anything with custom picture settings yet. I think I'll have the brightness thing figured out and then move to the picture settings.

Thanks, everyone!

Jerry

[Erik Norgaard]

Originally Posted by Jerry Winters

I own the xf300 and need to do a lot of outdoor shooting where it is very bright. Zebra set to 100%. What iris / nd filter settings do you recommend?

Also, I noticed adjusting the shutter angle resulted in darker video but I have a hunch this is not the intent of this setting.

Hi:

Iris, ND and shutter angle all affect the image exposure, but also affect the image in other ways.

If you change the iris, you will change the depth of field, if you want a fixed depth of field, then you can modify shutter angle or ND. Shutter angle will freeze each frame, in low frame rate like 24fps, motion may seem less smooth. ND simply reduces the amount of light without affecting the image in any way, all colours are absorbed equally, shutter speed is maintained as well as iris.

So, if you want a particular image quality that requires set iris and shutter angle then you need to use an ND filter to adjust exposure.

Btw, shutter angle and shutter speed are related: Shutter speed is absolute, set in time where as shutter angle relates shutter speed and frame rate:

shutter speed = 1/frame rate * shutter angle/360

Zebra is just a tool to help you with exposure.

BR, Erik

[Jerry Winters]

Awesome info, Erik! Thanks.

What f-stops do you try to stay between?

Jerry

[Peter Moretti]

Originally Posted by Doug Jensen

...
As for shutter speed, you should never adjust shutter speed to change the exposure. Yes, changing the shutter speed will change the exposure, but that should not be the reason you are changing the shutter speed. Set it once and leave it alone. A shutter speed that is too fast will result in a strobing effect that looks bad, and a shutter speed that is too slow will have excessive motion blur. There is a very narrow range of shutter speed on a video that looks "normal".
...

Doug, I just want to say that increasing the shutter angle in low light conditions can be beneficial. This is predicated on the subject not moving much.

[Erik Norgaard]

Originally Posted by Jerry Winters

What f-stops do you try to stay between?

Hi:

I don't know if you've got the XF300 or XF100, the 300 has a different (better) lens with wider aperture, better resolution, longer zoom etc.

I've got the XF100, the manual states that beyond F8.0 diffraction will cause visibly reduced sharpness, in fact in the menu you can limit the iris to not use smaller apertures. I prefer around 4.0-5.6 unless I want to achieve some particular effect with depth of field - which is limited anyway due to the small sensor.

It turns out that for the XF100 if you have ND enabled, the internal ND filter kicks in at F4.0 which might be just the behavior you want, but I'm still annoyed that they haven't separated the two.

I usually keep my shutter angle at 180°, for 25fps, that's 1/50s.

BR, Erik

[Nigel Barker]

Originally Posted by Erik Norgaard

It turns out that for the XF100 if you have ND enabled, the internal ND filter kicks in at F4.0 which might be just the behavior you want, but I'm still annoyed that they haven't separated the two.

I am not so sure that the Automatic ND filter on the XF100/105 is a real optical filter at all. I have a strong suspicion that it's all done in software by simply reducing the sensitivity of the sensor.

[Lou Bruno]

I purchased the TIFFEN 58mm ND filter(s) kit from B&H. It works.

[Jerry Winters]

I've got the 300.

FYI, I'm a novice shooting with a camera that is probably 'above me' but I am confident I can get better results with a superior product than by using something more at my level.

So, the lower the F-Stop, the shorter the depth of field is. Correct?

Forgive the elementary questions here. Just want to make sure I understand. If I use F4.0, items at different distances will be more in focus than if I use F2.0. Correct?

Jerry

[Graham Bernard]

Originally Posted by Jerry Winters

Just want to make sure I understand. If I use F4.0, items at different distances will be more in focus than if I use F2.0. Correct?

Jerry

Yes. Here's what I can achieve with my ancient XM2 SD. Having the iris as wide as possible and slapping on NDs. Hope you like the vid!

http://www.dvinfo.net/forum/attachments/canon-gl-series-dv-camcorders/16853d1268084069-shallow-d-o-f-gl2-shallow-dof1.wmv
Grazie

[Nigel Barker]

Here is a link to a handy calculator that will allow you to calculate the DOF for various cameras with different lenses & apertures. To check out the XF100/105 DOF performance select 1/3inch sensor from the drop-down menu & the focal length (the Canon zoom lens is 4.25 - 42.5mm). You will see that at the widest that pretty much everything from foot or to towards infinity will be in focus whereas when zoomed in DOF may only be a foot or two. Online Depth of Field Calculator

[Robin Davies-Rollinson]

There's also an app for the iPhone 4 which is a DOF calculator, which I can recommend.