Equivalent ISO for Canon XL1S

[Alan Van Vliet]

If I want to hand meter for tough exposures, what would the ISO be for the Canon XL1S?

I would guess it would be at 100, any ideas anyone???

Thanks in advance.

Al

Thanks for the replies and the info!

[Don Berube]

320 ISO

[Don Palomaki]

I presume the ISO 320 was for 0 dB gain. Adding gain is a bit like push processing film, 6 dB ~ 1 stop.

The camcorder (by providing instant feedback on a monitor) is in effect a large light meter allowing you to adjust exposure on the fly to obtain the best exposure for you rpurposes.

Because the sensitivity curve of the CCD does not match film, just using the the ISO rating may not provide the shadow or highlight detail you want.

Don Berube's number is a reasonable value or starting point, but youwill need to do some (maybe a lot) of shooting and evaluation to determine what works best for the sets and effects you want to achieve.

[Christopher Hughes]

I did a little few tests a while back with my lens meter, I used no expensive equipment to test it just using camera meter and light meter until I was happy of a match. I include din, just as the markings in din are not exactly inline with ASA, but its perhaps a percentage of a milimeter in diference, but I include din as those numbers seemed to match just that slight % or milimeter on my light meter so i can find the point each time. They are not exact, but on my light meters, close enough for me to test out lights and scenes for my own purpose. But with a little bit time, you can do your own little tests and get a good match on ur own light meter, rather than take my equations as gospel.


-3dB = 320 ASA (28din)
-3dB ND = +/-12 ASA (12din)

0dB = 800 ASA (30din)
0dB ND = +/- 25 ASA

[Roger Berry]

Hi,

This my first post in this forum and I'm a bit of a DV newbie so forgive any stupidity.

I'm not convinced that light meters, ISO numbers and even zones have no relevance in video. Here's how I figure it.

I think we'd all agree you can't set white balance in a totally darkened room or even in normal interior lighting with the lens stopped right down so you can't see anything in the viewfinder. So surely you need to start by finding the right aperture/shutter speed for mid-grey and go from there.

I did some experiments and came up with the same ISO/ASA number of 320 mentioned earlier using a Weston Euro Master and invercone. So before I begin, I set the camcorder acording to the meter reading, then I white balance, then I tweak the exposure.

This aproach has definitely improved my results... or at least it seems that way.

Now on to zones. I haven't really tested this theory but surely zones are still relevant. Maybe video only gives you five or six zones compared with film's seven but it still seems to me that zoning could be useful as a cross check against what you're seeing in the viewfinder or on the monitor.

Finally, as you may have gathered my background is in stills film photography and my standard light meter is a Weston. Does anyone know how to calculate a lux value with one of these? It's just that my XL1s manual says that the recommendedillumination should be "More than 100 lx" so I'd like to know how to check this.

Look forward to getting to know you guys. This is a brilliant form.

Roger.

[Charles Papert]

Roger:

As Don mentioned, the curves are different between film and video. Thus while it is possible to set an exposure with a meter in the midpoint of the curve, it doesn't really work to apply the zone system from there--you end up with non-linear, fractional zones at the bottom end and to a lesser extent, at the top.

I think that when it comes to comparing film and video, I prefer to compare video to a Polaroid rather than a traditional negative. What you see is what you get. If the highlights are gone, no amount of burning in will bring them back.

"What you see is what you get" works in one's favor with DV assuming you are using a good, calibrated monitor; you can set your exposure based on the final image rather than on the intense mental calculations that enter into proper film exposure. Never a need to bracket.

[Christopher Hughes]

Theres been lots of posts on the arguments FOR and AGAINST light meters. To just explain how I use my lightmeter, I don't use it as a failsafe way to calculation exposure of a shot, and I understand that film and video are different and all that stuff.

But what is very useful, especially for me, is that a lightmeter can be used to determine a shot or scene without needed to hump around heavy cameras and equipment. I can walk to a location and whip out my lightmeter from my pocket and see and approximate the light levels for the shot/scene. I can make little ajustments or change position very easily and then again whip the meter from my pocket and approximate the levels. I have saved time carrying camera around to a location, walking all the way there, to find as you get near the levels are not how u anticipated. So i saved all that energy instead of carrying my camera. Plus added bonus is, especially if your in a one camera unit, you can get someone to check out another location while your filming and then report back if you may need to carry lights of other extra gear to location. Saves carrying gear unnecessarily. And is a useful too for location scouting. I need to check out a stage production. Went to first night...checked out levels with meter, then took necessary gear on the next night. So I knew what lights, where to stick them, where to put the camera, etc....all without taking a single case to lift around, just a light meter and spot meter in my pocket.

So while a light meter may not be a perfect default tool to get your levels, it has its uses.

To Rodger - I believe I have a palmpilot program somewhere and a printed out chart I got from some website that was a conversion from ISO to LUX and viseversa. I could be mistaken as tipical u print out stuff and then you loose it. It may have been Lux to footcandles...I will try and see if I can find it.

[Christopher Hughes]

I cannot find the chart, but theres a website that has explanation and formula for Lux and ISO: http://www.natmus.dk/cons/tp/lightmtr/luxmtr1.htm

The writer states that its not 100% exact, but as the term we use in the UK, its a very "educated guess".

I believe one of the equations is :

Lux = 50 x fnumber2/ (exposure time in seconds x ISO film speed)

But I have not read it for a while. But im sure theres other websites just search in Google using a few keywords in what ur after.

[Roger Berry]

Hi,

Charles: I appreciate that the curves are different. My point there, I supose, is that WYS is not nedessarily WYG unless you're in a controlled environment with a properly calibrated monitor.

Maybe it's just that old habits die hard... My wonderful old Nikon FE and Bronica ETRs set to manual (which they almost always are) would never expect me to trust what I see in the viewfinder so why should I place total faith in my XL1s. Perhaps I'm worrying about the wrong things.

Christopher: Thanks. Your general points about using a meter were very helpful. I haven't got as far as encountering the situations you mentioned but I'm sure I will your comments will be filed away for future use.

Checked out the link you gave and now I understand all about lux... well almost.

P.S. Is Marsden Rock still standing? It's years since I've been up there.

[Don Palomaki]

A primary reason for light meters with film is because you do not see the results until the film is souped. And even with a light meter pros bracket the settings when they can to be sure they have a good exposure.

The fiewfinder image on a film camera is typically a ground glass using full aperture. Stop down to actual exposure and you will be able to judge depth of field, but expsoure is a crap shoot unless you have a calibrated eye. On a video camera teh viewfinder is usually a CRT or LCD panel that shows the actual exposure - a major difference. You can see what is happening to highlights and shadows. And zebra helps identify potentially washed out highlight.

But the bottom line is use what works for you!

[Christopher Hughes]

Marsden Rock collapsed a couple of years back. I was in living in Mexico at the time so never saw it, just on newspapers until I came over to UK. The rock split in two where the cave was and there was one thin column and one large one. To be safe they helped the little one on the way to collapse. So just the big one is there I believe so.

Where u living? You got family up in South Shields area???

[Alan Van Vliet]

Thanks for the input everyone,

I ran some tests using the 320 ISO as a starting point with pretty good results.

I am shooting high speed motion in bright sun against a background of dark windscreens. (outdoor tennis instructional videos) which has a tendency to overexpose the image. I will continue to play with the settings and let you all know of any findings.

Thanks for the great response.

AL

[Roger Berry]

Hi,

I live in Luton but come from Lancashire. Don't have family in the North East but about 20+ years ago, me and my best mate were on holiday in St Malo and met two lasses from Sunderland on Bastile night. Mine was called Alison but try as I might I can't remember her last name.

A few months later, we drove up and spent a weekend with them -- had a great time. They took us to Holy Island, Marsden Rock, Newcastle and a football match. It was Sund'l'nd's first match after they moved into the old first division and was against Southampton with Kevin Keagan as captain. That should help date the weekend if you follow football.

Thanks again for your feedback