2/3" HD lens on 1/2" F350 camera?!

[Mark McCarthy]

Hi all.
Need a wide angle lens for a big shoot in China soon. I use an F350 but can't afford to buy a 1/2" wide angle hd lens at the moment. Haven't had any luck trying to hire one either. Has anyone tried using a 2/3" HD lens, like the canon HJ11 with a 2/3 adaptor on the F350? Anyone with any ideas how this would work? I know I'd lose a little of the width when the shot is wide open because of the adaptor, but what would the picture quality be like? Would it be as good as a 1/2 wide hd lens? Be fascinated to know.
Many thanks, sparky

[Guy Cochran]

I believe that if you get an adapter to go from 1/2" to 2/3" lenses, that it'll make the lens longer (even more telephoto), so the less expensive solution may be to look at getting a Wide Angle Adapter or Wide Angle Convertor to place on the front of the lens Schneider Optics

Just make sure it's high resolution or "HD" for your 350 as some of the SD adapters I've tried are blurred at the edges and suffer from fierce chromatic aberration.

Whats the difference between a wide angle convertor and an adapter? Zoom through. See this video interview I shot a few years ago at NAB with the Century Optics (Schneider) rep. DV eStore Theatre - NAB2005 Century Optics

[Steve Phillipps]

2/3" lenses work fine on the F350, as Guy says, as long as they are pretty good ones. You do lose a lot of the wide end though. I'd think you'd be hard pressed to see much difference between an HJ11 an a 1/2" lens. Usually the adapters have an optic in though, so putting the 2x in (another optic) is not too pretty.
Steve

[Roddy Jamieson]

If your buying the adapter, go for one from True Lens Services, much cheaper than Sony equivalent. I use it often, works well and no glass in it like the Sony / Canon. The HJ11 will behave like a 6.5 to 7 mm, reasonably wide.

[Mark McCarthy]

Thanks guys. I may shoot some scenics shots of Shanghai with my 35mm adaptor and a 28mm canon FD prime lens. It takes a little while to set up, but may be the most cost effective method. Do any of you use an F350, if so do you own a wide angle 1/2" HD lens?

[Alister Chapman]

My experiences of using 2/3" HD lenses on my F350 have been disappointing. You must remember that the photo sites on a the CCD's used in the 1/2" HD cameras are much smaller then the ones on a similar 2/3" HD camera and tiny compared to an SD camera. As a result 2/3" lenses, even good ones tend to look soft compared to 1/2" HD lenses. In addition to that the different amounts of glass in the Prisms leads to a further optical mis-match that increases CA. It may be worth trying to find a wide angle 1/2" SD lens and trying that. I know several F350 owners using wide angle 1/2" SD lenses with acceptable results, although I have not tried this myself.

[Steve Phillipps]

I never saw that Alister, tried several 2/3" lenses and they all looked decent. Also my long stills lenses also performed well, and they are designed for 35mm, so much bigger format again. I'd always advise just to test, side by side, with a known benchmark (so in this case one of the 1/2" HD lenses).
You say "different amounts of glass in the Prisms leads to a further optical mis-match that increases CA", I heard that before, and did I not read somewhere that that is the reason why the 1/2" to 2/3" adapter needs glass in it, to compensate for that? It certainly does not need it for reasons of back-focus distance not allowing infinity focus, as there is a non-optical adapter on the market. I did, however, try the adapter with and without the optic and could see absolutely no difference in image at all.
Steve

[Alister Chapman]

35mm stills lenses do normally perform well. Although they are designed to work with a larger sensor (or film) the sensors have a very high pixel count and thus have a lot of small photosites, typically around 6 to 6.5 µm. Also the optics in stills lenses are much simpler than in a sophisticated video zoom lens as stills lenses don't have to stay in focus as they zoom (hence no back-focus on most). Most stills zooms are not true zoom lenses instead being vari-focal lenses. Longer focal length stills lenses tend to be prime lenses which are the simplest of all. This reduces the amount and complexity of the glass making it much easier to get good results, especially less CA. A well designed doublet apochromat will produce almost no CA and can be extremely high resolution, yet it only contains two simple glass elements. One element would be made from crown glass while the other made from a more exotic glass such as FPL-53. A modern TV zoom lens can have 20 or more elements in 16 groups. Half of those elements are doing nothing more than correcting aberrations.

Typical DSLR 6.5 µm pixels
2/3" 1440x1080 CCD has almost 7 µm pixels (this is what most 2/3" HD lenses are designed for)
2/3" 1920x1080 CCD has approx 6 µm pixels
1/2" 1440 x1080 CCD has approx 4.5 µm pixels

The glass in some of the 1/2" to 2/3" adapters is there to help compensate for the different prism thickness. However the refractive index of the glass in the adapter will be different to the refractive indexes of the different glasses used in the prism so there will be more CA.

My experience, based on 3.5 years of in the field use has been that 2/3" HD lenses are generally softer than 1/2" HD lenses when used on a 1/2" HD camera. Often the difference is not apparent unless you view the material on a 32" or larger full resolution monitor. With HD most people are using big monitors or TV's so the difference can be even more striking when using say a 50" screen. Of course other people may have had different lenses and had different results.