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2k, 240fps, canon glass....really soft images

I

Ian Planchon

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I have done some preliminary googling, but most of the results seem pretty old, so I have a feeling something has changed since they were posted.

I went out today to shoot some wildlife scenes with my Epic, it was setup in 2k, 240fps and was using a canon 200mm prime lens (its the longest lens I have access to at the moment, hoping to get the RED 300mm soon). At first I was just using the 5" touch screen, but it was so bright out with all the snow I threw my DP4 on. thats when I noticed that pretty much all the shots I was getting where the focus was set close to infinite was REALLY soft. the close up stuff was ok. what little research I did indicated that 2k, 240fps can look soft, but this is totally unusable. I am 99% sure it wasn't me just missing my mark as I rolled through the focus a couple times to check it, and the end result was always soft.

anything I am missing? could it be the canon glass? I borrowed it from a friend, its a 2.8, and it had a .9 ND filter in front of it.

would love to get this sorted out since I need to go re-shoot this now.

thanks!
 
The very first questions are:

- How far away was your subject?
- Was it a hot day?
- What aperture were you at?

The ND could also effect the image as well, but I'm betting those other questions will give you the answer you're looking for. Especially since you stated the close focus stuff was okay.
 
I would say 1/4 mile at the MOST

not hot, 27 degrees f

it was set at about f5 if I remember right.
 
i sometimes get soft images if there are very bright windows in the scene, snow, bright water...its a type of flaring.
as well, i think it might be a combo of that and 2k seemingly is a bit soft to my eye anyway, plus maybe a cheap nd filter can do it.
 
I don't use Canon lenses - so this is just really a bit of a checklist to help you sort out. Maybe Ketch or some other shooters that use(d) Canon glass can help in more detail.

Things to think about

A) the lens itself could be soft (throw it on a 5D and see what it's like at infinity)
B) Obviously your RAW has no sharpening added as per a DSLR and also you're looking at a 2K window on your sensor - so that adds to softness
C) Your flange/back focus might be out - and this might be due to swapping PL & Canon mounts (a recent thread on a soft lens or potential issue with a user's Epic ended up with a switching mounts & cumulative back focus problem)
D) Shoot settings and maybe the ND could also be an issue (presume it's a screw on?).
E) A combination of small elements of al the above (ie, soft performance, slight back focus issues and shooting in a 2K window) might just all be working together to cause the problem.

Maybe try a known lens you have that achieves infinity focus and then do some tests with that.

It's a case of crossing things off the list to get at the problem.

Hope that's useful?

Edit - just read Phil's reply and your response - that sounds like it may be the issue. I'd still check backfocus but distance and haze can also be a killer.
 
The ND filter is a cheap one for sure, its a cavision 4x5.6 filter, about $100. I had it in my matte box. back focus could be the culprit. I was thinking about that, but for some reason didn't give it too much thought. I typically don't use canon glass, I have all PL lenses, and they are tack sharp with the same setup. I know the lens I used is awesome on my buddies 5D, so I will check back focus next. I am assuming its possible without the RED focus, correct? just a standard focus chart?
 
Stephen Mick said:
If it's the Canon 200mm f2 or f2.8, I can pretty much guarantee that the lens is not the issue. Even wide open those lenses are hella-sharp.
Click to expand...

thats what my buddy said. he loves that lens.
 
Ian Planchon said:
The ND filter is a cheap one for sure, its a cavision 4x5.6 filter, about $100. I had it in my matte box. back focus could be the culprit. I was thinking about that, but for some reason didn't give it too much thought. I typically don't use canon glass, I have all PL lenses, and they are tack sharp with the same setup. I know the lens I used is awesome on my buddies 5D, so I will check back focus next. I am assuming its possible without the RED focus, correct? just a standard focus chart?
Click to expand...

Ian - this is the thread I was thinking of - it started as one thing then ended up about backfocus. http://www.reduser.net/forum/showthread.php?94591
 
Andy White said:
Edit - just read Phil's reply and your response - that sounds like it may be the issue. I'd still check backfocus but distance and haze can also be a killer.
Click to expand...

I did a shoot in china with a RED ONE, and they had the RED 300mm in 2k, 300fps AND a doubler, and the shot still looked shaper than mine. so I didn't think 1/4 mile would have been an issue. thats why I didn't give it much thought.
 
Ian Planchon said:
I did a shoot in china with a RED ONE, and they had the RED 300mm in 2k, 300fps AND a doubler, and the shot still looked shaper than mine. so I didn't think 1/4 mile would have been an issue. thats why I didn't give it much thought.
Click to expand...

Sounding more like BF then.

Do you switch mounts much?
 
Maybe give it another try at higher rez?
 
oh man. thats a good idea. can't believe I forgot to try that one! hahaha. will try that next.
 
It's not a good idea to use (glass) filters up front on lenses above 150mm
Filters that are not perfectly flat affect the image severely.
Try stopping down or jelling the lens in the back- the long lenses are pretty resilient to rear filtering.
It's the opposite for wide angle lenses...
Compare the results with and without the front filter and you will know...
 
Jacek Zakowicz said:
It's not a good idea to use ND up front on lenses above 150mm
Filters that are not perfectly flat affect the image severely.
Try stopping down or jelling the lens in the back- the long lenses are pretty resilient to rear filtering.
It's the opposite for wide angle lenses...
Compare the results with and without the front filter and you will know...
Click to expand...

good to know. I will try that as well. cheers.
 
Sounds like heat waves. It can be mighty cold out and they can still be a huge problem. It has to do with heat differential, not just ambient temperature. 1/4 mile at 2k with a 200mm lens in bright sun on snow would do it...that's my guess anyways. Especially since your close ups look great.
 
Any glass that put in front of a long telephoto lens could be suspect. And could just be this particular lens (on some Canon glass the backfocus can get thrown off by a simple bump. e.g. 24-70mm f/2.8)

Ultimately, however the correct test is to throw it on a 5D and see what it looks like. Post some stills and see if we jog our memory.
 
I will run down the list and see if I can rule things out, thanks for all the help everyone.

cheers
 
Andy White said:
Ian - this is the thread I was thinking of - it started as one thing then ended up about backfocus. http://www.reduser.net/forum/showthread.php?94591
Click to expand...


Andy, very astute, that was my nightmare on the shoot you speak about, and as much as you'd like to think it's everything but BF, it was BF.....and it sucks. It came from going from Canon to PL.....I have since bought a Red Focus but that's just a stop gap. I really wish there was something better and affordable. The Denz is 4500.00 plus another 4500.00 for the rig that checks the collimator. A real weak link in the whole changing mount game.
 
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