Manual Focus Method

[bddv]

I'm sorry if this is an old issue but a discussion arose the other day and I stood my ground, believing I was right, and now I'm not so sure. I could use some words of wisdom from the boys in the band.
Using a DVX100, can you zoom right in on a subject, focus, and then zoom back out for proper framing and have the subject still in correct focus. I did a search on this board last night and found a post that says yes, but I also remember a year or two ago, someone else asking this question and the answer was no. Something to do with how the zoom worked ... what is in focus at one zoom point would not neccessarily be in focus at a different zoom point.
I know this seems stupid and somebody is gonna say, "why don't you turn your camera on and find out", but I'd like to find out if there is any technical reason why it does or does not work.
Also, would there be any difference between the 100 and the 100a regarding this issue.

Thanks guys, and remember, Panasonic makes a great camera, but DVXUSER makes the camera great.

 

[taubkin]

Yes, the lens, if it is in good working order, should retain its focus throughout the zoom range.

For quality fixed lenses, like the DVX, it certainly works. If you are using interchangeable lenses, things might get trickier...

The thing is that the backfocus of the lenses, the distance between the lens and the background plane where the image is projected (in focus), can be off, and if it is onl7y slighly off, the wide end of the lens will not hold focus (that happens because backfocus is more delicate in wide angle leses than in teles). When using interchangeable lenses you have to always check for backfocus problems, and most cameras allow you to make the proper adjustments...

For the DVX, yes, it holds focus.