Problem with the 3x on XL2?
 

I was email'ing one of the sponsors about an XL2 quote and they mentioned trouble with the 3X lens, and to call for details. But I was swamped and they closed before I could call. The existing 3X threads on this board seem to state that there are no observable problems with the 3X. Is there _any_ known technical reason the 3X might not work well with the XL2?

On a side note, is a lens change on the XL2 big downtime? I've changed lenses on some big JVC's before, but only under rare circumstances (troubleshooting, etc). My immediate use for the XL2 will be run and gun documentary, and if I want to change lenses it means I'll have to carry another lens with me. That's possible, but dicey, and I'm terrified of getting crud on the bare "window" into the body. Makes me wonder if I should just get the converter.

If your plan is run and gun and you don't want to carry an extra lens, I would suggest geting the full zoom through wide angle converter and just leave it on. That way you can get wide or tele without ever bothering about changing lenses on the fly.

Hi Jeff,

I use both the stock 20x and the 3x on my XL2 and both work great. "Down time" for changing lenses is the same as on a 35mm SLR camera...just takes seconds for the actual lens change. NOT COUNTING the time to carefully unstow and stow the lenses, of course! So let's call it a minute.

Presumably, for run and gun, you'd want to just leave the 20x on the camera. It is a "long" rather than "wide" lens (42.3mm to 846mm for 35mm equiv when shooting 16:9) -- but then it has a 20x zoom range so that covers a lot of ground! I'd just guess that you don't need to get in really tight too often for most run and gun work? But if, on occasion, you did need to set up a really wide shot, the 3x will do the trick nicely. You'd just need to be in a situation where, if you were carrying a 35mm SLR and needed to change a lens, you could do it. And, of course, the GL2 is a lot more portable and less attnetion-catching -- in case that's important to you.

Are you shooting 4:3 only? If so, you could get nearly as nice a picture from a GL2 -- also a 20x Fluorite lens -- and pay about a third as much for it plus a good wide angle adaptor as compared to the XL2 with the two lenses. The GL2 is less "long" and slightly more "wide" at 39.5-790mm in 35mm SLR terms, whereas the XL2 in 4:3 is 51.8mm to 1036mm in narrow screen. With a WD58H adaptor, you'd widen the GL2 to 28mm equiv.

In my book, the XL2 really shines because of its unmatched WIDE SCREEN image. But, if you'll be using wide screen, the XL2 and its interchangeable lenses rock...have no fear of THAT!

Just food for thought.

Jeff and others. remember to TURN THE CAMCORDER OFF before changing lenses to prevent and shorts in the contacts. Bob

Jeff,

There is at least some anecdotal evidence (as in my experience, and a couple of others) that there is a back focus issue with the 3x on the xl2. I haven't had time to send mine in, but I got an email from a member who did, and was told by canon that they wouldn't be able to fix it...this is 3rd party so I can't say that all 3x lenses will have this problem...but mine does.

On the other hand..when focused..it's stunningly sharp...fantastic really.

Barry

Now, what does "back focus" mean?

Douglas

Theoretically, a zoom lens with proper back focus will maintain its focus plane throughout its zoom range. My 3x lens, when focused on an object at full zoom, will lose focus as it zooms wider.

Barry

Are you saying that the 3x lense will work great on the XL2 unless there is a back focus issue on the 3x which cannot be corrected on the XL2?

Is the back focus of these lenses somehow adjusted in the camera electronics??

Thanks.

JIm..

I'm saying this may be an issue...I have it...someone else has it... and he has not reached a conclusion with canon...

The manual 16x lens has a user adjustment, all others must be sent it to canon, (I'm not sure how they make the adjustment).

Barry

3X DOES have a back focus problem on XL2
 

I have heard (anecdotally) that Canon is aware that the 3X (with and without the 1.6 extender) will not hold focus over the range of the rack.
I was told Canon never intended for it to be used on the XL2.

I have proven the problem time and time again using 3X, pull in, focus, pull out - you are can now REfocus better than you should be able to. I am in 24p, 16:9 but doubt that is an issue, regardless - i am tired of yelling at my dailies after i trusted my focus settings on the 3X.

To its credit - when wide, the 3X plus the extender is nice for very large establishing shots where you can get away from vertical warping issues, but i was used to the XL1 where i could depend on the lense wherever i was in the focal range.

Does that mean you don't see this problem on the XL1? I do on the XL1s.

I shot with the XL1 for 18 months and the problem with the 3X was not there.

Are you SURE it is loosing focus? Because it is known fact that
when you increase the field of view on a lens (zoom out) you'll
get an appearance of softening since you are spreading the
pixels across the image. The image will look softer at the wide
angle due to pixel averaging, the higher the resolution of the
camera the less apparent this is though (so it should be more
obvious on the XL1 than the XL2).

This effect is also more pronounced on large vistas etc.

Also see this thread (2nd to last post by Chris):

http://www.dvinfo.net/conf/showthrea...486#post236486

Yes, absolutely. And here's the interesting bit. With the lens (iris) wide open and zoomed all the way out (minimum focal length) the best focus is full CCW whether you are focusing on an object (Sieman chart in this case) a few feet away or a tree line at "infinity"! This is true on both the XL1s and XL2 (on my XL1s and XL2 with my 3X lens anyway). Thus it's clear that the optical path from the flange to the chip surface must be different on the XL1 since it doesn't exhibit this behavior and we'd have to assume that any XL1 lens would perform differently on the XL1s and XL2 - not just the 3X (exception being those that have a back focus adjustment which the 16X manual does but I don't know about the 14X).

I suspect that it is not possible to focus this lens on distant objects when it is wide open. It feels as if you ought to go just a little further CCW to get things to snap in. This may explain why people have complained about landscapes taken with it (though aliasing could certainly also be an issue).

Remember that making a 3.4 mm (minimum focal length of 3X) lens is a real challenge. It isn't possible to have a back focus distance that short so the designers art really comes into play here. I guess the design trades were done to favor use in tight spaces and I suppose that is what this lens is really intended for.

For what it is worth I got to try the Canon 3x Wide lens for a while(borrowed from a friend) and I did see a bit of a backfocus issue with it on short distances. However outside on a "vista" type shot I zoomed and focused on trees over 100 yards away and zoomed out and the shot looked magnificent! However in a small 20 foot room I focused on a chair 15 feet away and zoomed out and it went out of focus. however the lamp that was 7-8 feet way was now sharp and seemed to mark the new focal plane. It's as if it moved closer as I zoomed out.

Since I was only borrowing I cannot comment on having it adjusted. If I bought one and it had this issue I would surely have it at the Service Center to be adjusted.

Having played with the Century Optics adapters for years I can honestly say that the Canon is the best looking wide angle adapter I have ever used. It is amazingly clean and sharp and with little barrel distortion at all. Great piece of glass.

AJ - Pardon my ignorance but what is CCW? I've never heard that term. Thanks.

<<<-- Originally posted by Jim Sofranko : AJ - Pardon my ignorance but what is CCW? I've never heard that term. Thanks. -->>>

I'm not AJ but I think it is an acronym for "Counter Clockwise".

And for the record I see the same thing as AJ on this issue.

Hey, you learn something new everyday! Thanks.

I have a 3x lense that I shot with all last summer on two docs with the XL1. I love the lense for handheld shooting as well as for wide vistas. The downside to wide vistas can often be the problem with the DV format dealing with small detail rather than the lense itself. Much depends on the subject of the shot as has been previously discussed on this forum.

I'm considering a camera purchase in the near future. One of the compelling reasons for me to stick with the Canon XL series is the 3x lense that I presently own. It can be a diificult lense to focus in low light on any of the cameras. But with a little stop it has tremendous DOF. (Depth of Field)

But with back focus issues, the question I have is...is the lense usable on the XL2? Does it mean that one needs to be a bit more careful on the focus or are there situations that it is simply unusable?

Jim,

It's not unusable. Realistically you are mostly limited in terms of using the motorised zoom somewhat, as the image may likely lose focus through the zoom range (this issue exists with the xl1s as well, its just harder to see as the xl1s image is less sharp to start with). If you want to use the zoom, you would want to be focused on a middle distance object, and try to keep your f-stop from 4-5.6, this should minimize any back focus problems.

I'm not sure yet that this issue is endemic to the design of the lens, but enough people have seen it to suggest that it might be.

Barry

It definitely exhibits backfocus
 

Hey Jeff,

My lens as well as my friends, exhibit the same back focus problem on the XL2.

It SUCKS big time because I thought the reason they kept the XL lens mount was for interchangeability. I'm pretty mad about the whole thing but until Canon releases a new lens, were pretty much stuck with it.

The good news is that even if you see this problem you can still use the lens and get excellent wide angle shots. You just won't be able to zoom in and focus and then zoom out and retain taht critical focus. Because of the shorter zoom this is not that beneficial anyway. I can tell if I am in focus just as easily with it zoomed or with it pulled full wide.

And my experiences with it once I focus is that is amazingly clean and sharp. The cleanest wide I have ever seen on an XL series camera. I have used the Century Optics adapters for years and find that they do exhibut a considerable softness on the edges at the widest angles and you will se some barrell distortion. I see absolutely no signs of either on the 3x lens. A superb piece of glass.

I am glad that a friend of mine let me borrow it but I am going to miss it when I give it back next week!

Spoke with Canon yesterday and they said to send the lense back for 'recalibration'. They would not admit any issues inherent with the 3X - XL2 combo, but did infer they had other calls on the same topic.

Will ship it out soon.

Please let us know if they actually fix it. If you turn out to be the guy that has worked out how to get this problem solved you'll be a big hero around here.

Will do - a bit nervous to take it out of production as we have come to depend on it...IF we stay wide. And Canon did not acknowlege a problem, they just offered to 're-calibrate' it.

I love all my Canon's from the XL2's to the new sweet little SD300 i just got - (if you are contemplating wait for the SD500 due out next month) - so i don't want to lose faith in them, but this lense does not work across the range so i hope to post back here in 2 weeks or so with good news.

Buzz, I am assuming its going to the New Jersey shop, not the one out here in California?

Yes - Vermont to Jersey....as soon as Presidents Day and the snow passes.

Buzz - did you find out any more information on the x3 lens and back-focus problems?

Here is a thread that I've started on similar problems:

http://www.dvinfo.net/conf/showthread.php?s=&threadid=39925

Maybe someone else could comments on their findings?

Tony,

The lens would have gone into the post today... so I doubt he has heard anything back. Interesting results on adjusting the back focus to fit the wide angle adapter on the 16x manual though. I am on the fence about which to buy, so Buzz' experience with canon should tip the scales.

I'm also on the fence at the moment (about buying the X3), but I've got to do a lot more footage and double check the sharpness of the Optex before I decide if its really good enough. First impressions (after adjusting the back-focus) look good, and maybe I don't need that X3 lens after all.

It would have been REALLY nice to have a X3 manual lens (come on Canon!). My Nikkor lenses work great on the XL1s, but even if I used a 13mm f/5.6 or 15mm f3.5 they wouldn't get me wide enough.

Judging by the extra amount of frame using the Optex on the 16X manual, it seems to give me enough space to work inside a boat, and the extra weight of the manual 16X lens + converter (compared to the 3X) should be an advantage in keeping everything steady in choppy waters, and with the MA-200 XLR on the back it should also help the balance.

What is the going rate for the Optex? I did a quick search, and could only find prices in pounds or euros - which seemed to be about 800 dollars US. There are three 3x lenses for sale on ebay right now, for 800-850 dollars. That seems to be the going rate. SO if I was going to spend 800 dollars, is it more efficient to get the OPTEX or the 3x with it's bells and whistles? Just part of what I am thinking.

Well, I got the Optex as part of a package, so I didn't pay the full price, and got it used but in A+ condition and mint glass.

With all the soft focus issues going around about the X3 lens, my thoughts now are seriously on keeping the Optex instead. It is a bit of bind having to adjust the back-focus, but if it means maintaining sharpness, then I'll live with it. The only issue with the Optex is that it is a big chunk of glass (although quite lightweight), and that is going to cause a few probelms with bright sunlight in or close to the edges of the frame. I don't think Optex do a lens shade for this (I'll need to look on their website) - but I should be able to find something to fit, as the inner flange has a thread.

If the Optex is indeed "not" a zoom thru then I'd say the 3x Canon is a better deal. IMHO

I am currently using the .7x Century Optics WA adapter on the 16x manual lens. It is full zoom thru and allows me to get telephoto and wide shots with one lens on the Camera. It is very clean and sharp except at the widest setting where there is a little fallof on the outer edges. The 3x Canon is much cleaner at the widest setting but I opted for this because I don't want to be changing lenses.

FWIW I have tweaked the Backfocus of the 16x Manual lens while I have the .7x mounted. There seemed to be a slight backfocus issue when I mounted it but a minor tweak and it is amazing sharp.

I must say having used the manual lens for a week and a half I see a major improvement in my shooting. What I mean is focus is dead on all the time. With the 20x I thought I was in focus but often would see I was just barely out when I viewed the tapes later. for whatever reason the manual control of the 16x just helps me snap right into perfect focus.

Marty,

Whats the price difference between the century and the optex?

I agree with the sharpness of the 16x. I couple it with the FU-1000 viewfinder for dead-on shooting, especially in low light. I've also used the 14x, and found it nice and sharp too, and enjoyed the manual iris ring.

I have never priced the Optex so I cannot say for sure. The .7x from Century lists at $799 I believe. I picked up a used one for $325 on Ebay sometime ago. I think you could get a new one from a reliable vendor for around $599 or so. There is a different model for the manual lens and the Servo lens so that may make a difference.

I have scrutinized the images generated with it and can only see the softness around the edge because I am looking for it. If you never compared it to the Canon 3x you might not even notice it.

I have the Mark 2 version of the Optex .7 lens.

I'm curious to what you say about the .7 Century + 16X lens being almost equal to the the X3 lens (except in the corners). I'm not sure how much difference there is between the .7 Century or the .7 Optex, but with the Optex being only part zoom, and needing to refocus with the back-focus knob to do so, then it may be that the Optex is sharper than the Century due to it being designed to focus in a narrower band, rather than compromising slightly to anable focus through the full zoom.

<<<-- Originally posted by Tony Davies-Patrick : I have the Mark 2 version of the Optex .7 lens.

I'm curious to what you say about the .7 Century + 16X lens being almost equal to the the X3 lens (except in the corners). I'm not sure how much difference there is between the .7 Century or the .7 Optex, but with the Optex being only part zoom, and needing to refocus with the back-focus knob to do so, then it may be that the Optex is sharper than the Century due to it being designed to focus in a narrower band, rather than compromising slightly to anable focus through the full zoom. -->>>

Century makes a .6x that is not zoom through and in my mind it is slightly sharper at the edges but shows more barrell distortion. An interesting note is that the .6x century is a single element adapter. Therefore the lens of the XL2/Xl1 needs to focus on that element directly. On the 16x manual you need to access the macro mode to achieve this. On the servo lenses the move from regular focus to macro is automatic and most don;t even know they have done it when they use this lens.

The .7x century is a zoom through and has 3 lens elements in the adapter.

As a side note when I used the .6x Century non zoom I had a hard time focusing even using the macro settings. It just wouldn't quite go sharp enough unless I tweaked the backfocus. SOunds like the same thing you are seeing with the OPtex. Is the Optex a single element adapter?

I love the 3x Canon lens but I have only used it on the XL1.

The pluses are that it has the 72mm front which is the same as the 16x lens and the 20x lens. This is nice for filter rings, adaptors, or a matte box, one size fits all of the Canon line of lenses.

The focus button is great so you can easily use that to focus which I end up doing most of the time anyway on all the Canon lenses. I tired of trying to manually focus with the servo. And if I can't maintain focus by zoomming in and then out, I should be able to simply use the focus button on the pull out during a shot.

Plus there is a tremendous depth of field with this wide lens at any stop.

I always was always under the impression that the 3x lens was overall sharper than the Optex. Please correct me if I'm wrong here.

Well, it's clear what we need is a 'shootout' on an XL2, with a 3x lens at both ends, and a 16x lens at both ends with the optex and century .7 adapters on it.

So, who amoung us has access to all three?

I have access to all but the optex lens....however on Friday I am returning the 3x to the friend who let me borrow it.

I don't have much time but if there are some basic tests that you'd like I could try to fit it in.

I'd like to get my hands on a X3 lens to test it against the Optex + 16X manual.

With the Optex you do not move the 16X into Macro mode, as the Optex will focus extremely close with the lens in normal mode.

With critical adjustments of the back-focus I'm now able to obtain extreme sharpness, and find it difficult to find much difference with or without the Optex in the sharpness stakes. I'm obviously going to need to place a lot more footage through the camera in varied light conditions before I can make more firm judgements, and also look carefully at playbacks on a large monitor.

I'm obviously still undecided about whether to buy a x3 lens, especially as now I have so much control using the Optex. Also, if I choose to use an XL1s & Xl2 with the X3 lens, I may encounter problems talked about earlier in this thread. At least with a manual lens you can adjust for slight differences between cameras and lens tolerances.

The still-frames shown in the x3 lens review shown on this DV site look extremely soft to me, and also under terrible lighting. I’d like to see some more outside footage using this lens outside in good light conditions.