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-   -   A1 lens limitations (http://www.dvinfo.net/forum/canon-xh-series-hdv-camcorders/120885-a1-lens-limitations.html)

Bryce Comer May 4th, 2008 05:45 AM

A1 lens limitations
 
Hi all,
Just wondering if someone could help me out with a problem i have with my XH A1. I do a lot of wildlife filming, quite a bit of which i use a Raynox 1.8 tele converter. I have found this lens to be great, but i have found that with or without this converter, i often find myself with a perfect close up of a bird or something, but when fully zoomed in, i can't get the focus at that range. I am guessing this is the limitations of the main lens, as it is the same without the converter.
Would a diopter filter help with this? If so, would it also work between the main lens & the tele extender to give me a closer focal range?

Thanks in advance,

Bryce

Annie Haycock May 4th, 2008 05:52 AM

Sounds like the same problem I had when using just the main lens. If you zoom in first, then focus, everything stays in focus at all focal lengths (or it is supposed to). The focussing is more critical on a telephoto setting than a wide angle, so if you focus on the wide angle first, by the time you zoom in, you find you're not on that critical point.

I know it's difficult with wildlife - animals just don't stay still enough for long enough.

A teleconverter is high up on my list of things to get this year, so any comments about using one are of interest to me.

Bryce Comer May 4th, 2008 06:03 AM

Hi Annie,
Thanks for the reply. What i meant though, was that if you are fully zoomed in, then the lens will only focus on objects at a certain distance from the lens. It's around about 6 feet or 2 meters with the tele conversion lens on, & a bit shorter than that without it. I am just wondering if a diopter would help this.

Thanks,

Bryce

Annie Haycock May 4th, 2008 09:05 AM

Ah, I think you are talking about the minimum focussing distance of the lens?

When you are on wide angle, you can focus down to a few centimetres, but when you zoom in, you have to move back quite a bit to get the closest focussing? That is pretty much the case with zoom lenses. Some cameras/lenses do have a close-focus option at the telephoto end - eg my Sony A1e - allowing much closer focus than normal.

If so, yes, a close-up filter on the front of the lens would reduce the focussing distance and you'd probably have to focus manually.

There is a pdf about the focussing distances etc for the Canon A1 with the raynox at (teleconverter and dioptres)
http://www.raynox.co.jp/english/video/egvideoindex.htm
just look down the page for Canon A1/G1 - it suggests the minimum focussing distance becomes 3.5metres.

Bill Pryor May 4th, 2008 10:05 AM

You might try a 1/2 plus diopter if you need to get closer.

Jonathan Shaw May 5th, 2008 01:00 AM

Agree sounds like you need a diopter, check out century/schieder, double element achromatic's... they are expensive but excellent.

Jon

Bryce Comer May 5th, 2008 03:27 AM

Excellent guys,
Thank you very much. I will look into getting one ASAP.

Thanks,

Bryce

Paul Mailath May 5th, 2008 04:57 AM

check out my recent post here

http://www.dvinfo.net/conf/showthrea...490#post868490

is that what you're talking about?

Bryce Comer May 5th, 2008 05:12 AM

Hi Paul,
It certainly sounds like what i'm after. Are you able to zoom in from further away from an object with these filters & still 1) get good shots, & 2) are you able to focus on subjects closer to the camera while still being zoomed all the way in? If i am going to get something like this, i think i will go for one of the more expensive, better known ones. I recently bought a tele conversion lens for my Dad for his stills camera while i was in Singapore. I didn't get to check it on a camera but was assured by the shop assistant that it was very high quality. When i got it home & gave it to him, we set it up & took some shots. The CA was so bad, the lens is useless for anything but a paperweight. So i think i will have a look at the Scheider optics +2 Diopter, or maybe even the Raynox set since i am very happy with the tele conversion lens i have of theirs.

Bryce

Paul Mailath May 5th, 2008 05:21 AM

I was able to focus on items on full zoom a couple of cm from the lens but the quality is questionable - I really just wanted to see what the results were, and for the price it was good to play around.

I should really do some tests with a focus chart and measure the distance to the lens.. but then again I should clean out the gutters.. you never know

Bryce Comer May 5th, 2008 06:05 AM

I hear you Paul,
There's probably a million & one other things i should be doing when i'm playing with my camera, but none of them seem half as much fun! :)

Bryce

Don Palomaki May 5th, 2008 07:25 AM

Canon also offers some diopters, however, not really marketed for their video cameras.

Jonathan Shaw May 5th, 2008 10:52 PM

Also remember that there are single and double element ones,

Single = Cheaper however you will see edge distortion

Double = More expensive but hardly any distortion (if any) E.g Schieder / Century

Bryce Comer May 6th, 2008 06:05 AM

Ok, so i looks like it's a choice between the Schneider optics 3.5 diopter or the Raynox macro lens kit which consists of 2 lens', 1x 2 diopter, & 1x 3 diopter, together forming a 5 diopter. I am very happy with the quality of the Raynox tele conversion lens i have, but really like the look of the Schneider diopter for its simpicity, & a 3.5 diopter will probably do me for what i need. The price is the only hurdle now, as the Schneider optics lens is almost twice the price of the Raynox. I would love to hear from anyone who has used either or both of these lens add ons.

Thanks,

Bryce

Don Palomaki May 6th, 2008 06:14 AM

The Canon models are 250D and 500D, available in a variety of diameters. (I've used one with a GL1.) Some more info at:
http://www.bhphotovideo.com/c/produc...e_up_Lens.html


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