••Fujinon TV Lens on GH-1...Don't Drool••

I have an XDcam, for video jobs, but I love the fact that I can use the (DSLR GH2 and 3) pretty well like a stills camera. Quick, fast, easy. I rig it with a Varavon loupe and a beachtek for audio, a couple of fast primes and a fast zoom. So, I suppose I'm rigged up as well, but strapping on EVF's, matte boxes, follow focuses is fine for contained shoots and interiors, but frankly I love the flexibility of concentrating on composition rather than worrying if the filter is clean or my EVF is about to run out of battery. Anyway, take your point and glad it works for you.
 
Worrying about a filter being clean....... EVF battery??????

My EVF will run all day on a VLock battery and powers the camera too. I worry about my filter being clean as much as you worry about your lens being clean.

Look we all have our own ways of shooting and setups. Whatever floats your boat.

Saying that a rigged DSLR defeats the purpose of DSLR shooting is just plain wrong though.

The 5D became so popular for video mainly due to the look it gave not for its small standalone form factor.
 
Clients will specify a DSLR shoot or a video shoot. Many don't like the slow set-up and reset times of multiple locations with a DSLR. Also, stuff on the move in daylight is a pain if you're rigged like you say. Great in a studio for product stuff or interviews, but really it's a specific tool for a specific job. I'm not talking about rigged - but overigged DSLR's. Some are done purely to look more professional - particularly on GH2's and their small bodies. You're right about the 5D though. Small fast primes and zooms made it popular, not banging on a TV lens. Also, if you've shot with a matte box all day taking out filters and swapping them all day, they take a lot more cleaning than a lens. I shoot pretty well every day on two bodies and can think of nothing worse than a great big unbalanced TV lens on the end of my DSLR which I then have to rig to use properly.
 
Ok, lets agree to disagree. I've explained that my rig never has any setup time whether shooting indoors, outdoors, handheld or tripod mounted. If you setup your rig properly, there is no slow set-up times and in fact, time is saved by not having to change over a heap of primes. I too like shooting with primes when I'm after a certain look but the OP was wanting a lens to zoom with. You just can't do that with primes or stills zoom lenses.

Balance your rig properly and that broadcast lens is no hindrance at all and actually saves you a heap of time not to mention getting you that shot that you couldn't get with your primes.

And small, fast primes are not what made the 5D so popular.
Clue: it's got something to do with the sensor size and price point.
 
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To reopen a twice-dead thread... Does anyone have tech experience with backfocus problems? This is a two-year long project for me, something of a side project that i've finally gotten very close to working. I have a pegasus iii (fujinon a14x8.5berm-28) b4 mount lens attached to a gh1. I adjust back focus (wide open aperture, zoom in, focus, zoom out, focus with backfocus, repeat until focus stays throughout zoom range). But i haven't been able to make it work.

When i zoon in all the way after back focus adjusted, the image looks fantastic, but when i start to zoom out just a little bit, it goes soft. Classic case of needs backfocus adjusted. At first i thought it might be a problem with the macro- the way the macro adjustment works it seems to adjust right along with the backfocus and it's not clear to me at all how the two work together (or against one another). I figured either i must be doing something wrong with the two or something must be off with the glass internals, and no budget to work with to have it looked at, it's cheaper to just buy another lens.

So i bought a canon j15x9.5b. The servo attached says j15x9.5b4. This lens gives me the same problem exactly- zooming in, image looks fantastic, but zooming out just a little bit causes image to go soft, just like the other lens, way too soft to be useful.

I'm using the ciecio7 b4 mount, because it had the best rep, but was also one of the most spendy. The mount has been rock solid though.

Does anyone know if there might be a different problem to look at, or are these lenses most likely both out of collimation?

Thanks

Rob
 
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It kindof sounds like your macro isn't locking or you may not be adjusting the backfocus properly. Make sure your macro control locks into place when you put it back on the normal setting. From what you said it sounds like you are doing the back focus properly, but just in case, instructions are below (also for others that may not know how).

The way to adjust backfocus is this: zoom all the way OUT to the widest zoom setting. Put your magnifier on the GHx, keep the digitally zoomed in area semi-close to the center of the image, and find a hard edge of something. Set your lens focus ring to approximately the distance of the object from the lens (most pro and broadcast video lenses have reasonably accurate distance markings). Then begin to adjust your back focus until the image becomes sharp. Since you have a higher end B4 adapter, the correct point will most likely be somewhere near the tick mark on the back focus. When the image is in focus as best you can get it, then zoom in. The focus should not change. If it does, correct it with the focus ring. Then zoom back out to full wide and check the focus with the digital zoom again. If it's in focus then you are properly adusted (or close enough). If not, then keep messing with the back focus in slight bits, going through those steps until you get it in the right spot. Sometimes you will get it first try, other times it takes some patience and you may have to go back and forth quite a bit.

Now, the macro. Backfocus adjustments move the rear element(s) of the lens closer or farther from the imager. The macro function moves the same rear element only _closer_ to the imager, with the space left over from backfocus adjustment. So if your backfocus were for some reason to be set where the rear element was all the way back, then the macro control would do nothing as there would be no room for it to move the element further. But the normal backfocus position range leaves plenty of room for macro adjustments. Of course when you go into macro, your focus will change as you zoom, because you are changing the backfocus by operating the macro control, but of course you don't normally need to zoom in macro anyway.
 
I talked to a tech, his opinion is the same as mine, i have two lenses with same exact problem, he thinks it's unlikely that both are so far out of alignment that they go out of focus so quickly when i zoom out, so more likely operator (ME!) error, or something wrong with the adapter or camera. I have two gh1's, both same problem, but only one adapter, and as you said it's a higher end one so not likely a problem. Anyway, one of the eng lenses has the macro and also a 2x doubler, the other has neither, so i have that one hooked up since it's the simpler of the two (least likely to suffer from operator error).

On the tiny viewfinder, it's impossible to see if distant objects are in focus, i'm already using 2x to cut out the vignetting, but i've been switching to 4x in the camera only when wide to make sure it's focused, i'm assuming that doesn't cause a problem with the back focus adjusting. Anyway, i did the backfocus with this lens (the one without doubler/macro) with same results, i'll try the other tonight (custom cam mount so takes time to change lenses).. Thanks for the info, i'll post after i try backfocus adjusting the 2nd lens.

Even though the tech thinks unlikley, i suppose given the age of these lenses they could both have internal problems, just seems unlikely..

Thanks
 
You need to use the focus magnifier, not the 2x or 4x zoom---it will let you see the 1:1 pixel view and be able to tell if distant objects are in focus. Another tip---DON'T set the lens to infinity and assume that it's correct for far objects---some are, some are not---a couple lenses that I have (even some that are fairly high end) will focus a slight bit past infinity. Not a lot, but it's enough to mess up your back focus adjustments. Pick something closer to focus on that you can get a good view of and estimate (or measure) the distance to it to set your approximate focus point.
 
I didn't have a chance to try the backfocus tonight, will have to do it tomorrow. The focus magnifier, that means the focus assist on the gh1? I never could get it to work in creative movie mode, i'll try to get it to work in one of the still modes then, i've never used them. Yes, both of the gh1 lenses i have do focus past infinity, thanks for mentioning. I didn't realize i could use something closer- most of the instructions i've found say to use something as far away as possible, but anything that will get better results than i have sounds great to me, i'll try this tomorrow.
 
Yes the instructions that say to use far objects all rely on the fact that you put your lens on the infinity setting. Which is fine IF your lens is perfectly aligned and won't focus past infinity. But IMHO it's harder to do that way because of everything being smaller and harder to judge precise focus. When you pick a closer object to focus on, you can more easily find a hard sharp edge of something or another to just focus best with. The downside of course is that you have to take note of the distance and set your focus ring there, and you may have to re-adjust several times to get it right if the distance markings on your lens are not exact.

Let us know how it goes :-D
 
I didn't know that, maybe that's where i am doing it wrong. I did try it with the other lens with the same results, but this weekend i am going to try it again with both lenses but focusing on something closer. I'll also see if i can find a cable to hook it up to monitor, not sure if that works since i haven't done it before.. Have seen some youtube videos that look really fantastic with both of these lenses on gh1, though gh2 with ETC mode might be better in some situations. I'll post results later this weekend, thanks you!
 
Thanks for helping with this. As it turns out, both of these lenses are *fine*! Like i mentioned, i'm using the 2x zoom in the gh1 to cover the sensor since these lenses just give a small circle in the middle. The 2x apparently is what's causing the problem, without 2x enabled, everything seems to look great though i haven't had a chance to zoom in post or use the lens with the 2x doubler, i'll do that this week. I was surprised how crappy the IQ was with the 2x compared to without. Someone told me that blowing up the size of the image is more complex than it might seem, so i guess it has to do with how the digital zoom is doing its thing. I'm hoping that shooting without 2x doubler and without 2x digital zoom, i can just use premiere to zoom in. Most of the shooting is under low light, so the 2x doubler won't normally be useable. Thanks for the help!
 
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