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Canon XH Series HDV Camcorders
Canon XH G1S / G1 (with SDI), Canon XH A1S / A1 (without SDI).


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Old October 7th, 2007, 12:17 AM   #1
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Is this "normal" or to be expected?

You all be the judge and jury!

Before this A1 goes back to the retailer and gets swapped out for a replacement next week (whose preformance I hope is greatly improved over the 1st unit which was dismal) I decided to bring it to church and give it one more chance just to make sure.

The audio guy (who I work with closely) who also bought a HD camcorder earlier this year for himself (in his case it was a Sony) was surprised to see first hand how limited the A1 was in letting in light with the iris wide open with the shutter speed at TV 60 or in manual at 1/60th.The test enviroment was a well lit church sanctuary where I've shot many services successfully with a pair of GL-2's.He confirmed my concerns that all was not well.

With the A1 fully out & wide,I then proceeded to demonstrate how much more light was quickly lost (above and beyond the general shortage of it in the first place without adding lots of gain) as I zoomed directly in towards the pulpit.Both of us could see the stops going by like a freight train while zooming in on the LCD.Started at F-stop 1.6 & ended at about 3.8 (or something like that) which was too dark.

Keeping that in mind,hence here are my basic questions:

a)Is this normal,to be expected and is there any A1 shooting mode where one does not lose a substantial amount of light (the exposure level)while zooming in to the desired depth? Is this all the A1 does/can do?

b)I then gave up on the A1,used my 2 GL-2's (which had plenty of light to operate from whereas the A1 did not) and you can be sure I didn't lose light when zooming in with those which has been my long term experience in that location under the same lighting conditions.

So what gives...Is this a further problem with the A1?

The above is very crucial to my shooting needs.If the A1 is not capable of holding the specified/desired level of light when zooming in.. this unit will not work for my intended purposes & usuage.

That's about the best I can explain the problem.

Please help unravel & explain this phenomenon.

Thanks again!

Bruce
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Old October 7th, 2007, 05:30 PM   #2
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Quote:
Originally Posted by Bruce Pelley View Post
With the A1 fully out & wide,I then proceeded to demonstrate how much more light was quickly lost (above and beyond the general shortage of it in the first place without adding lots of gain) as I zoomed directly in towards the pulpit.Both of us could see the stops going by like a freight train while zooming in on the LCD.Started at F-stop 1.6 & ended at about 3.8 (or something like that) which was too dark.
Take a look at the top of the lens, just in front of the focus ring right below the built-in stereo mic. You'll see some numbers there, and they look like this: 1:1.6-3.5 -- those numbers are telling you that the maximum aperture at full wide angle is f/1.6 while the maximum aperture at full telephoto is f/3.5 (also, I mentioned this in my XH Watchdog F.A.Q. page at http://www.dvinfo.net/canonxh/xhfaq.php).


Quote:
a)Is this normal,to be expected and is there any A1 shooting mode where one does not lose a substantial amount of light (the exposure level)while zooming in to the desired depth? Is this all the A1 does/can do?
It's perfectly normal and should be fully expected. The way to avoid it is to shoot in a manual exposure mode and set the exposure to f/3.8 to begin with, in order to avoid a change of exposure from occurring throughout the zoom range. Compensate for the light loss by adding gain if necessary, or shoot in an auto mode.

Quote:
b)I then gave up on the A1,used my 2 GL-2's (which had plenty of light to operate from whereas the A1 did not) and you can be sure I didn't lose light when zooming in with those which has been my long term experience in that location under the same lighting conditions.
Actually the GL2 works exactly the same way (in other words, just like the XH A1 it does not have a constant aperture lens), except the maximum aperture values are a little different: f/1.6 at full wide and f/2.9 at full telephoto. If you've never noticed that difference before, it's most likely because you had some other function automatically compensating for this change in exposure, whether it was shutter speed or gain. At any rate, just like almost every other camcorder, the GL2 does indeed lose light when zooming in, as has been previously discussed here: http://dvinfo.net/conf/showthread.php?t=37475

Quote:
Before this A1 goes back to the retailer and gets swapped out for a replacement next week (whose preformance I hope is greatly improved over the 1st unit which was dismal)
I can practically guarantee that you're not going to see any difference between the XH A1 you have now vs. a replacement camera.

By the way, what it so difficult about hitting the space bar after commas and periods and other punctuation marks? Your posts are hard to read because of this.
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Old October 7th, 2007, 05:58 PM   #3
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You need a Sony PD170.

(Out of curiosity, what was the Sony "HD" camera your sound man was using that was so much better than the Canon XH-A1?)
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Old October 7th, 2007, 07:27 PM   #4
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Well,since the GL-2 can and does lose light

while zooming as you have stated, even so it was never noticed as it was so slight to the naked eye. I didn't need to intentionally set it to compensate (as I wouldn't know how to do it anyways) as it apparently automatically compensated somehow on its own or maybe it was preprogrammed in.I never fiddled around with the gain on the GL-2.

How do you think the GL-2 is programmed/set-up so that no light loss is noticed when zooming in modes other than auto? As you know my preferred shooting mode is TV 60 w/exposure lock on. So, it is possible to set-up the A1 to automatically "compensate" the same way as the GL-2 does other than what follows immediately below?

If the f-stop is initially set to 3.8 (as suggested) in manual mode to avoid light loss while zooming, the key point is that at that level, it's already too dark to be usefull in the intended shooting environment so that defeats the purpose.It's a no win scenario because there is no control or constancy of the light levels while shooting if I choose to use the zoom which is vitally necessary without sacrificing & jeopardizing quality. Why should I have to add gain in order to have enough light?I don't get it.Why doesn't the A1 give one enough to start with?

Are you telling me that only the A1 auto mode won't do this to me?

I was hoping there were more options than this!

Thanks Chris for your informed and thoughtful response.

Jack,as soon as I know what the audio guy has I'll let you know.I've heard about it but he's never brought it to church yet.
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Old October 7th, 2007, 07:49 PM   #5
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Expected

HD needs more light because it has more pixels on roughly the same sized CCD chips, so it is to be expected. Make sure that you do not have the ND filter on.
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Old October 7th, 2007, 08:09 PM   #6
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All the electronic lenses on all the 1/3" chip cameras perform this way. The reason the XH A1 lens stops down more is that it zooms in more. You'd have the same problem with a PD170. A $10,000 lens will not do that, but they don't put $10,000 lenses on $4,000 cameras.

Make sure your ND filter switch is off. And you might want to try zero db gain instead of -3 if that's what you're shooting at. Or if you're at zero, try a +3 if things are still too dark. Make sure all the auto stuff is off. The only solution if you need more than an f3.5 is to not zoom in that far. If you must zoom and have to zoom in that far, then you'll have to use a higher gain, which will make things grainy.

In doing a comparison between the XH A1 and a DSR250 (which has the same chips as the PD150), I found them to be almost identical, with probably about 1/4 of a stop going to the 250. That was zoomed in fairly tight to a dark place under a table, to a cardboard box with fairly neutral reflectance. At different focal lengths and different light conditions, the cameras might be farther apart, I don't know since I only checked that one setup.
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Old October 7th, 2007, 10:20 PM   #7
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Bill, when you say make sure all of the auto "stuff"

is turned off,what exactly were you refering too? Please elaborate & give detail. Thank you!

Yes, the ND switch is definitely turned off. Right now I have the setting in the low position to 0 db gain.What baffles me is the sizable difference in the amount of light coming into the GL-2 (which is more enough to do the job) as compared to a so-so amount of light coming into the A1 even when wide open at f1.6 which only gets worse when zooming.That's why I reffered to the A1 as a apparent light hog earlier on in the thread.

Here's why zooming is so essential & can't be ignored or minimalized in its importance in my particular case. When in the church shooting setting,I'm positioned in the back of the audience between the back pew and the wall. That means the speaker or other service participants are probably I'd say about 75 feet or so away from the lens on the platform. I film the main action and another volunteer on occasion does the close-ups and pans. That means in order to get some kind of "variety" & to try to make the program a little more interesting for the viewers (seeing that there's only 1 camcorder on the front at all times) I vary the depth every few minutes by zooming in or out to include more or less of the congregation.In addition, I vary the depth with just the pastor & the pulpit itself in the picture.That means every time I zoom one way or the other the light balance is affected and put out of whack for the environment and it sure would show up on film!

If I didn't do the above, (assuming I had enough light in the first place coming into the A1), it would be a lot more stagnant,the picture would tend to be too far away from the action and it would be too limiting & boring for someone to watch. So apparently I'm caught between a rock and a hard place now.So what are my choices:

Eiether I'm zoomed in with lotsa gain on in order to try to cope with light loss or not zoomed in with the picture being sort of a wide panarama-bird's eye view.IMHO its not a great choice especially as I aim for quality as one can only compromise so far.

I'd welcome a solution other than auto.

Thanks for your imput.

Bruce
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Old October 7th, 2007, 11:15 PM   #8
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If you are getting the desired results from the GL2, why don't you just stick with the GL2?
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Old October 8th, 2007, 12:10 AM   #9
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Quote:
Originally Posted by Jack Walker View Post
You need a Sony PD170.

(Out of curiosity, what was the Sony "HD" camera your sound man was using that was so much better than the Canon XH-A1?)
I shoot a lot at work with a VX2100, and can tell you that in a well lit church--which I shoot tons of with my A1--there's truly a negligible difference between the A1 and the VX2100 which is the consumer version of the PD170. I just shoot on "Automatic" with both, and get simply beautiful results with the A1 every time--like today.

On my shoots I am constantly receiving comments on how great the images look. I do not apply any color correction or other than basic editing processes on my church shoots, I don't need to.

Bruce, there is simply nothing a GL2 will do better than an A1 in those conditions (well lit curch that you describe).

Similarly, there is simply nothing a PD170/VX2100 will do better than the A1 in those conditions you described, as well. It's fully comparable to any top SD cam when used in SD mode in a well lit stuation such as you describe. I know from first-hand experience from using both extensively in similar circumstances.

Whether it's the cam, or how the settings are, I don't know. I now suspect it's got something to do with how the settings are. . I guarantee you, when set up and used correctly--(which can be defined in this case, as just leaving it on "auto") even carelessly as I discovered--the A1 will deliver the goods. It is I have found, very flexible and not some super-finicky cam that only functions in a limited number of circumstances.

Maybe your cam does not function correctly in TV mode? Try another mode and see if you get the same results. Try going back and setting the cam to its factory default settings. Then try again. Just plain old "automatic" seems to work for me just fine in those conditions. Try it, just for the heck of it.

Last edited by Steve Wolla; October 8th, 2007 at 12:18 AM. Reason: added info
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Old October 8th, 2007, 01:25 AM   #10
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I'm with Bill on this one..

side by side a DVX100 at 9+ gain up the A1 with 12+ gain, comes mighty close (a tad brighter in fact) and just as clean. Ive never needed to shoot a ceremony at 9+ or even 12+ though..

With the A1, the fundamental element above all other uses for the camera is to ensure your scene files are tweaked out. There is soooooo much control available with the A1, it isnt funny.. it took no more than 5mins to set up and also, by having the ability to dial in WB in a numerical value, matching the A1 with any other camera is a no brainer.
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Old October 8th, 2007, 01:48 AM   #11
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Hi Bruce.............

OK, let's cut to the chase here.

May I suggest you beg, borrow (or, dare I say it) steal, a decent hand held light meter and go measure the incident light available at the target you are trying to shoot, and let us know what the reading(s) are.

This is the only independant source of hard info we will have on this problem.

Comparing this camera with that camera is such a circular argument it goes nowhere.

I assume (as you didn't say) that you are shooting SD not HD?

If you are shooting SD and the difference in the percieved light levels (or the reaction to same) is as extreme as you say, it would appear to indicate there is a problem with the camera.

It may, of course, indicate that problems not visible with the previous camera are now "in your face" with the A1 due to a major jump in resolution or the handling of material, even in SD.

I would ask one (or two) questions:

Why are you shooting at 1/60th in an obviously challenging light environment?

Why not flick the camera into "Auto" everything and see what it can do?

As I cannot forsee anything happening in the Church which will require a fast shutter speed, drop it to as low (in manual whatever) as is required and see if that suffices ?

[I realise some of these suggestions have been made previously, but for completeness can't exclude them].


I do hope you don't have a dud camera, but it would be heartening to learn that it was a dud camera and not a dud camera series that was the problem in your circumstances.


CS
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Old October 8th, 2007, 09:54 AM   #12
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Bruce.

Take the camcorder and a good monitor to the church some time during the week when you can experiment with various settings to find what works. If high quality video of the service is important, find a good location from which to shoot, not just from the back of the church, and consider adjusting the lighting.

Most A1 users would not want to lug about (or pay for) a HD lens that maintained f/1.6 through out the 20x zoom range. As a point of reference check out the Fujinon 18x zoom produced for a JVC camcorder with 1/3" CCD. It weighs 3.3 pounds, about 2.5x the weight of the XH-L1 lens, and is priced around $9000.
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Old October 8th, 2007, 11:04 AM   #13
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Bruce,

I hate to sound like a jerk, but I think your low-light expectations might be a little extreme. There are many people who feel that cameras should magically be able to see as well as the human eye in challenging lighting conditions.

The fact is, the Human eye has had millions of years of evolution to see as well as we do, and our brains have evolved to compensate for in these situations, giving us a clear, 'noise free' image even in the worst lighting (aside from pitch black).

The Canon XHA1 is rated with an ISO of around 320. This is a fairly decent rating. at 6db gain, it should double the apparent ISO to 640, which is very fast.

I use a 35mm adapter which takes 2 stops off the image (redrock.com) Even with this adapter gobbling up light, I managed to shoot an entire short film in the middle of the night in a moving car using very small kino-flo lights, and not much else.

I have always found the XHA1 to be superb in lowlight. Try upping your gain settings. The noise is fairly invisible up to 6db, and certainly acceptable at 12db. Try playing with your custom presets to boost your pedastal, add noise reduction (for higher gain settings), play with your gamma curves.

I don't think this is a matter of poor camera performance, but more an issue of too-high expectations.

Try these settings and tell us what happens?

F-stop: 3.6 (zoomed)
Shutter: 1/30 (double your light, good motion characteristic)
Gain: 6db
ND: Off
Pedastal: Bump up a few notches
Gamma: Default (less contrasty, more info in the darks)
Knee (blacks): Stretch
Shoulder (whites): Low

Shoot in HD, so that there is more info to post-process with, and so you can get the full dynamic range off the camera.

Give it a shot in at least 20 foot candles of light. Anything less, and I doubt you'll get what you're looking for.

Having owned a GL2, it handled lowlight very well, but only at high gain levels. The 1/4 chips it contained were rated lower than the XHA1, and trust me, the A1 handles low light much better and cleaner.
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Old October 8th, 2007, 11:15 AM   #14
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There is no way the GL2 under exactly the same conditions would be better than the XH A1 in light requirements. I'm not doubting your observations, but there is something else going on. If you're zoomed back to a wide angle, shooting 60i at a 1/60 shutter speed and the GL2 is set the same way, you'll see that the XH A1 will want less light than the GL2. If not, there's something not set right or some problem with the camera.
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Old October 8th, 2007, 01:43 PM   #15
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Hi Bruce:

I have read this and your previous thread, if you want your problem solved you gotta be more detailed and more systematic. No one knows your settings, no one can see the location, and no output has been provided, and what you write is vague and non-objective.

To give everyone something objective to work with, do this:

Set both cameras in all manual, disable everything auto, white balance and gain. If something runs auto, we have no idea how this influence the final result. For the moment forget about noise reduction, colour correction and other details.

Set f-stop, focal length, shutter speed, fixed gain, ND, etc. to same or comparable values on BOTH GL2 and A1, note down these settings. Set them as close as possible in the same location at the site where you will be shooting.

Record 10-30 sec with each. For the A1, record 10-30 sec in both SD and HD. Provide a frame dump from each sequence, labelling which is which. If possible also, get a light-meter reading as an independent reference.

This will allow everyone to compare objectively the performance of the two cameras.

Then try to change one setting on both cameras, and repeat the recording, produce frame dumps again. You should try this: Use the minimum zoom and max zoom you will be using at that location. Try max aperture and fixed aperture 3.x (whatever it is). Carefully note down all the changes in settings you do. If you don't care to write down at location, just say it as you record each sample. Then write it in your next post.

This will allow us to see the performance range of each camera. This, with the previous, will allow us to guess about general bad performance, or if you got unlucky with your A1 purchase.

Next. Change manual settings of the GL2 to achieve the desired result note down the settings you use. Try to set the A1 with equivalent settings. Post the result.

This will allow everyone to see what you're trying to achieve and give advice on how to achieve that. It will also allow everyone else to use this thread for future reference so they can learn how to solve similar problems.

Thanks, Erik
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