Highlights burning out / CA ??
 

Hi guys.

Ok I've been out running a bit of test footage with my HD110 + 2/3rd Canon lens. I'm pleased with the performance on the whole except for a tendancy to burn out/purple fringe the specular highlights.

Is there a way to solve this issue? I'm a bit worried as I bought this camera mainly for a film I'm making on bugs and with bugs come sharp speculars of course.

Heres the footage - http://www.uwolchallenge.com/mattemp/dragon.mov - Look specifically at the dragonflys wings on 15secs.

Very interested in your thoughts on this?

I am interested in this as well as I encountered similar problems with my 201. In the viewfinder the image appeared washed out, although the ND was set to 2 and aperture F16. Some of the images looked too bright when viewed later.

Svein Rune

Hi again guys...anyone any views on this?

Is it something in camera or the lens inability to resolve the very bright highlights and thus blowing them out and creating abberation?

Hi Matt, Looks like straigtforward lateral chromatic abberation to me, classic. You didn't say what lens you're using? Most of these video lenses, even very expenisve one have some CA, many of them are appalling hence the need for some of the new cams to have CA reduction feature. You can remove these in post production, very much like people do on stills. I'm not an editor but know quite a few who have worked on my material and I believe you more or less pick the colour of the CA with a cursor and desaturate that colour, problem solved (more or less).
Have you tried any of the micro Nikkors? A lot of the real high quality stills lenses have minute amounts of CA and blow the video lenses away in a lot of ways, and the MF micro Nikkors (55mm and 105mm in particular) are top notch.
Good luck with the film.
Steve

Thanks for your response Steve, that makes interesting reading and sense.

I'm sure I could remove it in post but I'm just not prepared to continually do that. Its funny you mention the 55mm Nikor. I'm buying one in the next couple of days for the macro side of the project. From what I've read things don't get much sharper than that!

The video lens I'm using is the Canon YJ19x9KRS. I used to use the XL2+stills lens and in terms of usage the video lens is WAY better. Everything about it is easier to handle and use and I get the same reach as a 300mm stills lens! However I am now starting to think I'd need to go up a few notches to get very sharp results without the CA...!!!???? What do you think, any opinions or options for good 2/3rds glass that doesnt cost a fortune!

The Canon YJ lenses are pretty close to the bottom of the pile in terms of lenses to use on your camera I'd say. They're SD rather than HD, they're also low-end SD - they're "Pro" lenses as opposed to "Broadcast" lenses. They're also simply video lenses which I don't put much faith in anyway!
I'd say you need, ideally, a highest quality 1/3" Canon or Fujinon zoom, but they're bloody expensive. But I do think it's worth trying some good Nikons. If you get the 55mm be aware that there are many version, some probably better than others. I've got the f2.8 and it's stellar. Only thing dor bugs is it might be a little short, consider the 105 too, I have the f4, but I think they're all good. Check out http://www.naturfotograf.com/index2.html for good lens info.
I do think you may have to accept doing at least some work in post too, not ideal I know but I think it's something everyone has to live with these days.
Steve

With lenses, you pretty much get what you pay for.

To avoid CA like you have here, apart from swapping to a better lens, you could simply avoid shooting in high-contrast situations - particularly where there is a lot of back light.

Also, test the lens at different EVs. It will perform better at certain apertures, you need to find which ones work best.

Hope that helps,

Liam.

As far as I know Liam, CA of this type is not depndent upon aperture, but you're right with regards to sharpness, you tend to find that lenses perfomr best about 1-2 stops down from maximum, but don't go below about f5.6 as you run into defraction problems which severly limit resolution.
Steve

Thanks for your input on this guys. Basically I went for the 2/3rds lens because it gives me the reach I need. Using a video style lens is functionally so much easier to use than stills glass and gives you such a large focal range. However if it comes at the cost of IQ then I'm not so keen. Care to suggest any 2/3rds broadcast lenses that might give sharper/less CA results ? I can't find online reviews on these type of lenses unfortunately....makes it tricky to know what to look at.

I could go for the nikon 80-200 f2.8 if I go the stills route. I'm going to see the results the 55mm Micro gives picture wise and that will give me more of an idea I guess.

Mat, things like Fujinon and Canon 22x zooms (HJ22x7.6 etc.) are fairly standard, coming in at anywhere from £12-20,000 (haven't checked the prices lately), then there are really pricey ones like Canon Cinestyle lenses, and HJ18x28 (great long telephoto going upto 1000mm at £22,000) and the HJ40 (10-800mm but about £35,000).
I really would look at stills lenses though, something like an 80-200 f2.8, Sigma 120-300 f2.8 etc would give good reach and good image quality and you're talking about maybe £1500.
Steve

Hi Steve, yeah I certainly don't have that sort of money to spend on glass. Do you think moving into the broadcast range SD glass as oposed to the 'pro' range might up the anti some what? Do you know of anywhere that has reviews on broadcast lenses such as these?

If you spending those type of bucks
 

you might as well buy the new Fujinon 18x4.2 BERM 1/3 inch lens, I noticed this lens sneaked in, and nobody said anything, basically the 18x4.2 with a 2x extender built in, that gives you a 4.2 - 151mm, I mean it doesn't get better than that, the only thing is, as there's scant info about and examples about the performance of this or the 18x4.2 lens, it's a big leap of faith.
I remember one forum member posted some grabs from the 18x4.2, there still is some CA, but nowhere near as bad as the stock, and it's resolving power is heaps better.
And now there's the BERM version, it should be the one lens does everything for the event videographer! Just don't know how much you'd loose in quality engaging the 2x converter????

Or, just win lotto and say darn it all, and buy what you want!!!

Will be interested to see how you go with this, give the 16x credit for what it is, but it's wearing on me....

Adam

Matt, again I think it'll come to down to getting what you pay for. The broadcast SD lenses will be better than the Pro ones, they're just crisper and have less aberations. Though saying that, if you got something older like a Fujinon 15x8 I have heard dealers say that even the cheap modern lenses perform better. I was trying to sell a Fujinin 8.5x5.5 2/3" lens a while back and when they came out they were top spec and cost a fortune, but that was maybe 15 years ago and I was told that the new low budget pro lenses would outperform it so it wasn't worth much. Not sure I believe it though, as I've seen very good performance from these older lenses that were top of the range in their day, and because few people buy SD stuff these days you can pick up bargains. Check out www.bblist.com I would say though that I would tend to go for a proper HD lens, and a 1/3" lens at that if possible.
Best thing I suppose would be to try different lenses out if you can get hold them.
Steve