|
|||||||||
![]() |
|
Thread Tools | Search this Thread |
![]() |
#1 |
Regular Crew
Join Date: Apr 2007
Location: Alton in Hants and Swanage in Dorset, UK
Posts: 45
|
Softness at maximum zoom - knowledge & fix?
I often have to site the Z1 at the rear of audiences, far from the subject. At almost maximum zoom, even in well-lit situations, the image invariably looks soft. Clearly the best option is to site the camera more closely. However this is not always practical or acceptable, so a couple of thoughts:
a) Is there a replacement lens or a telephoto add-on option to permit full sharp HDV-resolution images at such distances and zoom levels? I am considering obtaining a 35mm adaptor, which may be relevant. b) For the Z1 as given, assuming mid-range f-stop (say), what's the greatest zoom level one can use before the softness effect essentially violates the "high definition"? By this I suppose I mean when the circle of confusion (due to imperfect lens, not DOF) is the same size and an HDV pixel. |
![]() |
![]() |
![]() |
#2 |
Wrangler
Join Date: Dec 2002
Location: Mays Landing, NJ
Posts: 11,790
|
I think something else may be going on here.... I shoot performances from the back of the theatre, over 100 ft from the stage, and never noticed the "soft" phenomenon you describe. I use a Century 1.6x teleconvertor lens on my Z1, and it helps me move in a little closer.
Are you focussing manually while you're zoomed all the way in? If you focus while wide and then zoom in, you might get softness at full zoom since focus is more critical there (less depth of field). I find that autofocus doesn't work well for performances. Also, what is the sharpness setting in your picture profile? I find the default a little too soft for my liking and have kicked it up a few notches. |
![]() |
![]() |
![]() |
#3 |
Regular Crew
Join Date: Apr 2007
Location: Alton in Hants and Swanage in Dorset, UK
Posts: 45
|
The same softness has happened on many gigs at nearly full zoom where the scene is typically a single speaker, Wide to Mid Shot. With camera on a locked steady tripod, I normally zoom in fully and use expanded focus view, sometimes with peaking. I have also tried using temporary (push button) autofocus in case I made a mistake. Sharpness has always been 11. Iris at the most recent gig, which was well-lit, was a comfortable f3.7 with 0dB gain and 1/50 shutter. I tend to underexpose slightly, in order to get clean highlights (levels to be raised and curved off gently in post).
My colleague always sits nearer to the speaker (10-20 ft) using a Sony TRV33 DV handycam on auto-focus, achieving a clearer image overall (despite more jpeggy artefacts etc.). Embarrassing! At shorter range though, like 20ft, the Z1 image is as expected sharper than the TRV33. |
![]() |
![]() |
![]() |
#4 |
Inner Circle
Join Date: Aug 2005
Location: Atlanta/USA
Posts: 2,515
|
I'm afraid something is wrong with the optics of your camera; try renting another one and confirm. As Boyd stated, there are no known issues with the sharpness on the Z1.
|
![]() |
![]() |
![]() |
#5 |
Major Player
Join Date: Jun 2005
Location: West Point, MS
Posts: 313
|
We have 10+ of the Z1U's and all of them zoomed all the way in with focus set at infinity are a tad bit out of focus. All the Field Producers here know to go to infinity and barely move back with the focus ring almost to infinity but not to infinity and that seems to bring everything into a crisp focus. It took us a while to figure this trick out but seriously all of our cameras see this issue and the trick works with everyone of them, back off of infinty just a bit. THX
|
![]() |
![]() |
![]() |
#6 |
Regular Crew
Join Date: Apr 2007
Location: Alton in Hants and Swanage in Dorset, UK
Posts: 45
|
Curious! I'll have to try comparing with another Z1 then. Many thanks for the replies.
|
![]() |
![]() |
![]() |
#7 | |
Wrangler
Join Date: Dec 2002
Location: Mays Landing, NJ
Posts: 11,790
|
Quote:
I think David is using the correct methodology: zoom all the way in, switch to expanded focus, and make the image sharp. Before shooting a performance, I do this for various locations on the stage and make a mental note of the distance readout (in meters) so I can have some confidence with manual focus on the fly as I shoot. If you are going to infinity, then backing off a bit, you're probably getting it into the ballpark but it really depends on exactly how far away the subject is and what your iris opening is. Since our operas tend to be rather dark, I'm almost always shooting wide open and that makes focus more critical. |
|
![]() |
![]() |
![]() |
| ||||||
|
|