back focus issues with Sony HDW 900

Markus Rave · August 6, 2004

I have shot a commercial last year using the Sony´s HDW 900 Cine Alta. It was the rumour that the backfocus might change when the camera gets hot. And so it was. The assistant had to refocus one out of three times he checked.

Since I will be shooting with the CineAlta again, I would like to ask if any of you know about the back focus issues with that particular camera or if Sony has fixed that problem. If they fixed the problem, how do I tell I will be shooting with a newer model?

Thanks

Markus

Elhanan Matos · August 6, 2004

As far as I know Sony has not done anything to fix this problem, I may be wrong. But if you need a quick solution to this problem you should check if your rental house carries a back focus alignment device, like the Zeiss Sharp Max. They are very easy to use, and they are the quickest way to adjust the back focus on your lens. If your rental house does not carry one, you should ask them to get one for you. They don't cost much, so i will assume they do not rent for much either. Good luck with your commercial.

Kevin Zanit · August 6, 2004

I have not heard of a fix from Sony either. I believe it is more of a lens issue (some being more prone to back focus issues than others). What lenses were you using?

Kevin "Elhanan did not call me back tonight, but I will forgive him ;)" Zanit

Markus Rave · August 6, 2004

Unfortunately the camera comes from a rental house 300 miles away. Last time the viewfinder was very unsharp and had a soft picture. I always double checked with the monitor on set. I will have to take what I get. The rental company must have made a very low package price. In Frankfurt, where I am based, the local rental has a Panasonic HD. But it offers not enough resolution for the production. I will have to take the DVW 900 or shoot 35mm if the budget allows to do so. No need to say what I opt for.

I have used Fujinon Standard HD zooms. But I don´t think it is a lens issue. A own a DWV 700 and it gets hot, too. I never had any problems with backfocus since more than 5 years now using Fujinon optics.

Well, it seems I have to introduce the assistant to this problem again when we use the HDW 900.

Thanks for your help.

Markus

David Mullen ASC · August 6, 2004

Well, it's harder to see back-focus problems with standard definition video, which is one reason why the problem didn't seem as bad until HD came along where focus is much more critical. And it doesn't help that the camera gets so hot internally.

I check back-focus at every lens change, and if the same lens stays on the camera all day, then once in the morning, once after lunch, and after an change in location with a big change in temperature. Working with a zoom, it's not a big deal to check it now and then. The problem I have is with primes where I feel obligated to check it at every lens change (although they say you don't have to once you checked them once for that location), which is tedious enough to make you want to stick to zooms.