Wide Angle Lens Converter for GL / XM

[Brad Higerd]

Presently, I do not have a wide angle adaptor for my GL2, but I am entertaining the possibility of obtaining one (most likely the Canon 0.7X).

This is my question: does a wide angle adaptor have any influence in the sharpness of the GL2's wide angle footage. As noted in other threads, the picture sharpness on the GL2 can suffer from a lack of sharpness in the wider shots. Does this (or any) wide angle adaptor increase/decrease the sharpness of the footage if the framing of the shot was matched; by matched I mean that a zoom was applied to the adaptor to create the same frame as taken without the adaptor.

In addition to the Canon model, I am also curious as to the clarity/picture that might come from a Century 16:9 adaptor. My wife tells me she feels cheated by the lack of a full picture, but that never stopped me from doing what I wanted to do. If you have any input on this subject (the adaptor not the marriage), I would be interested as well.

As always, I am grateful for your assistance.

[Ken Tanaka]

Hi Brad,
Well, since nobody's chimed-in here I'll take a swing.

Many folks would say that cameras with chips smaller than 2/3rds inch are generally poor for wide-angle shots, and the wider the shot the worse it gets. To some degree I agree.

Nevertheless, that's what we have to work with, eh? I frequently use the WD58 adapter with my GL2 and have not noticed degradation. In fact I think it's probably the best accessory investment you can make, aside from a good mic.

[Graham Bernard]

I've used this Canon accessory in some really tight places. Couldn't have done it without it.

Degradation? I'm not techie enough, but I do come from a background of 3 opticians in the family and my Optics courses in school did tell me that the more "glass" you put in front of a camera or an eye come to that, will "absorb" to some extent the light coming through it.

That being said, I'm fussy about what I see on the final product I do. If you've got a chance to do a Look 'n Feel - Try before you buy, see if you can convince your local cammy shoppe to allow you to do an in-house test - yeah?

I will say that the WD58H does make the XM2 a little front heavy. This is my only criticism.

[Graham Bernard]

Sorry Brad - I just re-read your wide-angle adaptor post. Is this the WD58? Sorry for being a bit dense on this!

[Tom Hardwick]

If you add a wide-angle converter and zoom up to match the camcorder's zoom lens at it's widest angle, you should have *exactly* the same shot. Easy to verify, and all tests I do with wide-angle converters have this as one of the parameters. Stills taken to memory can then be opened in Photoshop for detailed examination.

Of course adding three more elements in front of your 20x zoom's 12 elements won't go un-noticed, but a good widie should be almost transparent to this test. Of course there are losses in that flare is increased, there's a small light loss and de-centering of elements can cause slight sharpness losses. A perfect converter won't degrade the image at all, but we're far from perfect.

tom.

[Ken Tanaka]

Sage remarks, Tom. Which prompts me to add that whatever wide-angle adapter you choose, Brad, be sure to get an appropriate les hood with it. Canon's WD58H comes with a hood. You will inevitably encounter lens flare, some of which can be eliminated by a good hood.

[Brad Higerd]

Thanks for all of your feedback.

Concerning the lens flaring issue raised by Ken: Do I need to be concerned about this indoors?

And concerning the 16:9 adaptor: Would such a device have a significant influence on the video if I were to compare it with generating black areas above and below standard (4:3) video?

I really like what PBS is doing with the newer semi-widescreen documentaries. Does anyone know what equipment/techniques they are using?

[Ken Tanaka]

<<<-- Originally posted by Brad Higerd :
Concerning the lens flaring issue raised by Ken: Do I need to be concerned about this indoors? -->>>

Yes, you do Brad. Especially if you light your scenes. But even if you usually just use existing light any point-source lights can cause flare, even common table lamps or track lights.

Looking at Century's w-a adapter offerrings, it looks like they do not provide for a hood. I hope that this is incorrect. It's hard to believe that Century would not appreciate the value of such an accessory, although Canon sold the WD-58 sans hood for several years.

[Hans Henrik Bang]

Brad, not something I know a lot about, but my impression is that by adding a 16:9 adaptor (anamorphic), it will allow you to shoot 16:9 footage while still using the full resolution of the camera. The image will be "stretched" in the vertical, but this can then be corrected in post.

Thus if you use standard shooting mode and add black bars afterwards, you throw away resolution. If you use an anamorphic lens instead, you shoot in full resolution.

Another example (of something I know a lot more about) is anamorphic DVDs. Most movies are presented in some kind of widescreen format. If the DVD is 16:9 aspect ration but not anamorphic, part of the resolution will simply be thrown away by recording the black bars at top and bottom. Your effective resolution will thus not be 720x576 but rather 720 x 432 since the rest of the vertical lines are just black bars.

If the DVD is instead anamorphic, the 16:9 image will be stretched vertically to utilize all of the 576 vertical lines. If you play back on a widescreen capable device the image will be squashed back to the correct aspect ratio so that within the black bars you still have 720 x 576.

In other words non anamorphic throws away 25% of the resolution.

Another example would be 35 mm film. Sometimes movies are shot "matted" so that black bars are present on the 35 mm negative. This throws away film resolution too. A better alternative is to put an anamorphic lens in front of the camera, so you shoot a stretched image on the whole of the 35 mm negative. In the theater you will then put a "squashing" lens on the projector so that the resulting image is widescreen but still using the maximum resolution of the medium.

The numbers given are for PAL. For NTSC it will be pretty much the same ratios, just different numbers.

Now did that clear up anything or just further obfuscate the matter?

Hans Henrik

[Brad Higerd]

Hans,

What I'm trying to make sense of is that the resolution provided in my rendered DV video will seemingly negate that extra horizontal lines of resolution gained by the 16:9 adaptor. Will the vertical compression of the 16:9 footage really be any better in post?

Brad

[Hans Henrik Bang]

Brad:

I guess it really depends on your target medium. If you are going for VHS or regular broadcast, the anamorphic squeeze will not help you at all since all the preserved resolution will be lost in the final copy.

If however you go for a DVD (anamorphic mode) or some kind of high res application, there should definately be a difference.

Be aware though, that resolution isn't everything. One of my most beautiful DVDs is James Cameron's "The Abyss" which for some reason was done non anamorphic. It still looks great due to other factors such as careful compression etc.

Tell me more about your project if you need better advice.

Hans Henrik

[Tom Hardwick]

I'm sure I'm right in saying that Cameron has always shot Super 35 since The Abyss, Hans. This has meant that if you buy the 4:3 version of T2 or Titanic films you actually see more than was shown at the cinema and at the same time fill your 4:3 TV screen. There's slight snipping of the outer left and right borders, but overall (off VHS) I've preferred the full screen version simply because the 2.35:1 looks so soft on a domestic TV.

tom.

[Hans Henrik Bang]

Tom, you are absolutely correct. Abyss was shot in Super 35. That is basically a variation over standard "soft matte" shooting, where the space for optical sound tracks have been used for picture instead.

This gives an aspect ratio on film of about 1.6:1 but the point is that the film is still shot with an aspect ratio of 2.35:1 in mind.

So whenever a movie is shot "soft matte" (or super 35) there will be extra information on film in the top and bottom of the image. This is information that the cinematographer does not see or care about when shotting the film, and often includes boom mikes etc.

Subsequently most soft matted movies when shown in full screen will be "pan and scanned" meaning that a zoomed in box will pan around the image so that you see a 4:3 window into the widescreen version. Some movies are better at this than others. James Cameron as a notable exception personally oversees the pan and scan process of his movies.

Usually the P&S process results in peoples faces cut off, people talking from off screen etc. In a standard 2,35:1 movie what you see in fullscreen might have lost 40% of the material shown in the theater.

In case you haven't guessed it by now, I usually run away screaming when I see a "fool screen" version of a movie :-)

For additional information I stumbled upon a couple of good links:

http://www.digieffects.com/frames/tr...lmtovideo.html

Or for some examples of widescreen vs. fullscreen:

http://www.widescreen.org

Hans Henrik

[Tom Hardwick]

I like your terminology Hans: "Fool screen"! I'm like you, I detest pan and scan, but take a famous line from Cameron's Terminator 2. Schwarzenegger reaches down to Hamilton and says, "Come with me if you want to live".

In the 2.35: 1 version his hand is cut off at the wrist by the mask when he reaches down to her, yet in the 4:3 version you see right to the tip of his fingers. Everything else in the frame is as the widescreen version, yet picture edits such as this cut out more than would appear. Is his hand clenched in a fist? Are his fingers outstretched in a welcome? Has he even got hold of her?

Sometimes less is less and more is indeed more.

tom.

[Hans Henrik Bang]

Interesting example Tom. I am almost tempted to go rent T2 now and see for myself.

I also like those DVDs that have full screen on one side and widescreen on the other for examples. You can watch a scene, flip it over and then rewatch it right away. One of my favorite examples of this is "A few good men". It has a beautifully shot widescreen version on one side, and an atrocious P&S version on the other :-)

Hans Henrik