problem with .7x Century Adapter...sample included

I

icicle22

Well-known member
I have the new Century Optics .7x WA adapter that is full zoom through on my XL2. I was initially totally blown away by it. It brings the focal range back into the DVX realm on the wide end but still zooms much further than the 10x of the DVX. The perfect solution for me. But on my first real shoot I found that I was having a hard time focusing. I watched the footage and the majority of it was soft, even out of focus. I use the technique of zooming in tight on a subject, setting critical focus, and then zoom out. With just the stock XL2 lens this works like a charm. However when the .7x is added the picture goes slightly out of focus when I zoom out. The bad part is it can be hard to see this on the XL2's little 2" LCD so much of my shots got ruined.

I did a little experiment by zooming into an ornament on my XMAS tree and then zooming out and I can reproduce this everytime. I then did it with just the stock lens and it stays in focus fine. Is there anybody here that has tried the .7x adapter, even on the XL1 or DVX100 that can verify if this is how the lens behaves by design or if this is a flaw? Here is a link to the footage to prove this issue exists (For me):

http://www.iciclestudios.com/images/xl2/co_wa_focus.wmvx

rename the .wmvx to .wmv to watch it on your PC.

I will be calling century to find out their thoughts.

Thanks
Marty
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

hmm...maybe its just me, but for some reason it looks like there is some sort of focus searching going on, like the autofocus is on and searching...
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

There's definately focus hunting going on there. Either that, or you were trying to adjust the focus while and after zooming out.
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

[quote author=Glenn_Gipson link=board=XL2;num=1104337336;start=0#2 date=01/03/05 at 05:13:34]There's definately focus hunting going on there.  Either that, or you were trying to adjust the focus while and after zooming out.[/quote]

I stopped one time and refocused halfway through the zoom out. The camera is not in auto focus so the only hunting you see is me! that being said I should not have to hunt as it should retain focus in the first place!
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

I have no idea on this one; I remember hearing something about the XL model having an issue with back focus? Is this it?
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

That sounds precisely like a back focus problem. Well, almost. Are you 100% sure that the camera is in focus when zooming back out after focusing without the adapter?
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

What follows is the response I sent privately a few days ago to an email I received at Century. While, since the problem is most easily noticed with the attachment in place, leading to the conclusion that there must be a problem with the converter, it is most likely a lens issue.

My response:

First of all I am sorry I was unable to respond sooner, I have been using up some excess vacation as the year ends.

Please bear with me, because it is extremely unlikely that there is anything wrong with your .7X converter.

We would be happy to inspect and test your unit if you send it to us.

We have a Canon XL2 with the 20X lens here. I have personally evaluated the .7x on this lens. The lens is very similar to its predecessor the 16X. We have sold thousands of these for use on the Canon XL1 and the Panasonic DVX-- with very few complaints or problems, so while I will not say it is impossible that the unit is defective the problem you describe does not seem consistant with a problem in the converter.

If you achieve sharp focus at maximum telephoto and the image goes soft as you zoom wider the zoom lens itself is the likely problem. The .7x effectively reduces the focal length of the zoom. Depth of focus, the area of acceptable sharpness on either side of optimum focus (forgive me if you know this-- it is sort of like depth of field but at the image plane instead of the object plane) gets smaller and smaller as the focal length becomes shorter.

This can mean that if your lens has a slight backfocus problem, or the zoom curve is almost out of spec, it might seem ok (tho you say you are seeing "something" in the lens alone) but be unacceptably soft with the .7X in place.

If you zoom in auto focus mode does the lens remain sharp?

The converter contains no moving or focusing elements, and once you focus thru it and achieve sharp focus it should not change as you zoom wide--- unless the problem is in the lens.

The most critical test of the quality of the converter is typically at telephoto. The converter does have some lateral chromatic at wide angle and as is typical in converters (and the lens itself) is not as sharp at the edge of the field as it is in the center-- but is still very good.

Please email me and let me know what you would like to do next. If you bought the camera from a local store I would see if they would allow you to try the .7X on a different camera, or put a different lens on your camera and see if problem persisits.

It will be most noticeable when the lens is near wide open. Stopping the lens down increases the depth of focus.

Best Regards

Bill Turner
Century Division
Schneider Optics
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

Bill. thanks for the explanation, it does make sense.

It makes it very difficult or me to buy this converter (which I am very interested in). I can only imagine the response of my local Canon dealer if I were to take the XL2 back and complain about an effect that only exists when the Century Optics converter is fitted. (In Singapore I can't try before buying, because the converter would have to be ordered specially.)

I just wonder now if this problem is inherent in the 20X lens, but only shows up with the converter attached? Is anyone on the forum using this converter with good results? I'd appreciate more user feedback.

Richard Hunter
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

I don't think this is only a converter issue but an issue inherent to the Canon XL1 and maybe the XL2?
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

[quote author=jaegersing link=board=XL2;num=1104337336;start=0#7 date=01/03/05 at 16:24:08]Bill. thanks for the explanation, it does make sense.

It makes it very difficult or me to buy this converter (which I am very interested in).
[/quote]

take your XL2 to the place that sells the .7 lens you wish to purchase, and just test it on your camera.
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

[quote author=Rich Lee link=board=XL2;num=1104337336;start=0#9 date=01/03/05 at 20:57:17]

take your XL2 to the place that sells the .7 lens you wish to purchase, and just test it on your camera.
[/quote]

Not everyone has that luxury as most local shops do special order only on these types of items. Unless you are in NYC or LA it can be tough to get to see any of these cams and accessories before buying.
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

You can always return the item, yes? Contact Century and explain the concerns regaridng the attachment, Perhaps you'll be able to return if there is a problem?

Still, as Bill mentioned. There are no moving parts in the .7 This backfocus issue is rampant I think with the "XL"' 's
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

No, I cannot return this particular item as I bought it from a private owner who bought it from a licensed vendor. I am not complaining about the adapter directly. I intend to send it to Century to get approval that it is within specifications. And if they are so kind they can mount it on their XL2 and make sure it is functioning properly. According to Bill Turner they have done this with others and it works fine.

I was simply responding that it is not easy to find a camera shop that just has these items on hand for us all to try before we buy. In the bigger cities, yes. But I can travel to Pittsburgh, Cleveland and Columbus and won;t find a dealer with an XL2 in stock or any "higher priced" accessories. There is just not enough of a demand to warrant them keeping stock on these.

Peace!
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

icicle:

I understand completely, if the attachment is not useable for your purposes, regardless of the reason I hate to see you get "stuck" with it. The only thing I can urge anyone is to find out exactly what the seller's return policy is and thoroughly test during the return period.

I know this is easier said than done, sometimes an intial check looks fine and then much later in a more critical situation a problem becomes apparent.

I look forward to checking your unit thoroughly, please send it to my attention and let me know when to expect it.

Bill Turner
Century Division
Schneider Optics
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

My dealer in Singapore has to order the converter specially for me, so I don't have any way to try it out on my camera before ordering. Of course I will be able to put it on my camera before handing over any money, but nobody wants to take the risk of being stuck with something that cannot be used (even if the problem ultimately lies with the Canon lens).

Anyway I have updated the dealer with the latest info from this forum, and they say they will contact Century to find out what their position would be if they order a converter and it turns out to have the focussing issue on my camera.

Another question for the people on the forum who appear to have some prior knowledge of XL1/2 backfocus problems - is there any remedy available for someone who has a camera/lens with poor backfocus adjustment? Are Canon able (and willing) to fix this?

Richard
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

[quote author=jaegersing link=board=XL2;num=1104337336;start=0#14 date=01/05/05 at 02:28:42]My dealer in Singapore has to order the converter specially for me, so I don't have any way to try it out on my camera before ordering. Of course I will be able to put it on my camera before handing over any money, but nobody wants to take the risk of being stuck with something that cannot be used (even if the problem ultimately lies with the Canon lens).

Anyway I have updated the dealer with the latest info from this forum, and they say they will contact Century to find out what their position would be if they order a converter and it turns out to have the focussing issue on my camera.

Another question for the people on the forum who appear to have some prior knowledge of XL1/2 backfocus problems - is there any remedy available for someone who has a camera/lens with poor backfocus adjustment? Are Canon able (and willing) to fix this?

Richard[/quote]

Canon will absolutely fix this problem for you at no charge on new in warranty cameras. The problem that comes into play is this. There is always the potential to send in your camera and lens and have them recalibrate the backfocus to "factory specs" and then get the camera back and it still exhibits this annomaly. I am not saying this always happens but it can. I had a problem with my XL1 years ago and sent it in and it just kept coming back saying "meets factory specs". They never really fixed it until the 4th time. My concern is that I will send it in and this will happen. And then Century may say that there lens is within "factory spec" also.

At this point I could "theoretically" have a combination of camera and lens that is unusable and with both companies claiming that they are within spec, there is nothing I can do. Again this is the worse case scenario. Maybe I'll ge lucky! But it should be fixable!

I hate to be a pessimist but my experience with most tech support on issues like this is that if it is not a broken switch or a busted knob that you can clearly "see"is broken, then sometimes it gets dismissed easily and a basic checkup is done and it gets sent back saying "checked out within specs".

Thanks
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

The Backfocus problem as far as I remember was only a major issue in the first run of the XL-1 as it was a problem with the stock lense they were shipping and its focus plane in relation the camera CCDs. I purched one of these first XL-1 and had to deal with it, I ended up setting the backfocus properly myself, but it was always touchy because it was a defect in the lense. I eventually purchased an Optex manual zoom lense which I was able to control the back focus easily and it worked beautifuly after that. I really cant imagine that since the XL-1S they have continued to have such a major issue with the back focus since they use a different lense on that, and certainly a better lense is shipped with the XL-2 at least I would hope :)
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

I have never owned an XL1 or XL2. However, from what I have been able to gather via my reading of posts at dvinfo.net, The BackFocus issue is a problem that has persisted since the introduction of the XL1 the and continues to do so ( albeit in a somewhat more limited manner ) today.

I have read about owners who finally purchased the 16x Manual Lens after giving up on Canon's ability to resolve the BF issues ( after several attempts ). In fact, Chris Hurd and other XL2 gurus suggest that anyone concerned about BF issues should purchase the 16X Manual Lens as opposed to the standard 20X Lens.

Sorry!! This issue continues to haunt the XL cameras today ... :o
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

[quote author=NewBee link=board=XL2;num=1104337336;start=15#17 date=01/09/05 at 20:57:11]In fact, Chris Hurd and other XL2 gurus suggest that anyone concerned about BF issues should purchase the 16X Manual Lens as opposed to the standard 20X Lens.
[/quote]

May I know where they say this? I've just looked quickly through Chris Hurd's Watchdog pages, and can't see mention of any back focus issues at all. There is some discussion of soft focus at small apertures, but I think that is a different problem altogether.

If you can provide a link, that would be great.

Richard Hunter
 
Re: problem with .7x Century Adapter...sample incl

Re: problem with .7x Century Adapter...sample incl

I didn't see this in the Watchdog pages. I did see it as a response to a flurry of questions regarding nagging BF issues and the 20X Lens. I don't have the exact links at my fingertips.

Are you the same Richard Hunter on dvinfo.net? If so then I am surprised that you have not seen these posts ...
 
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