FS7: Sony 28-135 soft in center crop mode

Ben Scott said:
Except the large print was downsampled from a 4k sensor.
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But that is not how you described center scan. I take issue with your using the term "blowing up". You can shoot HD down-sampled from the full 4K sensor or center cropped from the 4K sensor, but never is HD on the FS7 "blown up".
 
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Take issue with what you like. If we're going to be pedants we both know that 1920x1080 does not = 1080p resolution post debayer.
 
Doug, have you noticed this issue before? I just happened to run a test before the event and it's a good thing I did. I ended up taking the camera out of cc mode. I hope to run some tests next week with a resolution chart. I would expect the softness using an extender.
 
Centre Scan is definitely softer - 100%. I use it every weekend shooting weddings and can tell from looking at it while shooting -> Its noticeably more difficult to nail focus as well (and the peaking isn't as sharp)
Even knowing that, I use it all the time because I can get shots I can't get without it (or don't have time to swap lenses). Would I use it for controlled situations where I have time? No.

From Doug's video, as I haven't done a side-by-side to prove it (Thanks for doing it Doug!)-> Massively obvious which is which
CC_Test.jpg
 
it really depends on the sharpness of the lens. My 55 and 85mm Zeiss Otus show nothing you wouldn't know in was in crop when I put on a 24-105 i can def. see decreased sharpness the new Fuji somewhere between the Otus and the 24-105
 
icarusfilm said:
it really depends on the sharpness of the lens.
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That pretty much sums up my opinion. If I was shooting HD I wouldn't hesitate to use it if I wanted the extra range with the excellent lenses that I own. But how often am I shooting in HD? Very seldom anymore. And how often am I shooting in HD and I want center scan? Almost never.
 
When shooting HD in a documentary seeing I set the S&Q to crop and I use it to capture closeups in slow motion when the verite is shot out clients like it and the execution is quick.
 
Ben Scott said:
Take issue with what you like. If we're going to be pedants we both know that 1920x1080 does not = 1080p resolution post debayer.
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I'm confused. Saying that the center crop 1080p "isn't really 1080p" would be the same thing as saying that full sensor 2160p isn't really 2160p, right? It's actually 1080p isn't it? I've never heard anyone rate the resolution of their camera lower because of its Bayer filter. (Unless the center scan on the FS7 isn't a true 1080p crop?)
 
BarryLichtner said:
I'm confused. Saying that the center crop 1080p "isn't really 1080p" would be the same thing as saying that full sensor 2160p isn't really 2160p, right? It's actually 1080p isn't it? I've never heard anyone rate the resolution of their camera lower because of its Bayer filter. (Unless the center scan on the FS7 isn't a true 1080p crop?)
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The sensor is 4k. The image is approximately 3.2k if memory serves me correctly. In this context (and as I said, if we are being pedants) I was talking about downsampling that image and having a proper 1080p image vs having a less than 1080p image and displaying it as 1080p.
 
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That's 3.2k before you use significant compression which muzzles everything.

Imo the fs7 in 4k mode once you nip the boom out of the top of frame or level a horizon (aka you should shoot 10% "safe") will deliver quality HD

Any other mode is going to be well below hd at the end of the chain.

Some will think this is typical SMM bunkum - but if one sees what an f35 delivers (imo a true hd camera) or downscale a raw still from a pro Dslr can one disagree?

That doesn't stop me using any mode though on a typical job because content is king so I do what is needed to get it.
 
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Yeah same. But it's the whole reason everyone shot 5k for 4k delivery on the old Red Epic-MX, and are now doing the same with 6k and 8k on Dragon/Helium.
 
On lense sharpness is it worth considering a 2/3 lens with a 1.4 converter to get the best from this mode - such lenses are, I guess, designed to have very high lines per inch over a small projected image circle
 
Ben Scott said:
Yeah same. But it's the whole reason everyone shot 5k for 4k delivery on the old Red Epic-MX, and are now doing the same with 6k and 8k on Dragon/Helium.
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And that is before one starts making uprught and square versions of ones content - which can require huge safe areas.

While I am very happy to watch 2k even in the cinema (skyfall looked great) I can appreciate the need to capture commercial imaging in far higher resolution
 
I tested this a little under 3 years ago with the F55. I shot the same scene with the same prime lens and only repositioned the camera between full scan and center scan to keep the subject the same size in the frame.

Test 1 Clips: Frozen Bush 200MB (ProRes)
(contains 2k center scan mode and full scan mode with same framing)
DOWNLOAD

Test 2 Clips: Jingle Balls 280MB (ProRes)
(contains 2k center scan mode and full scan mode with same framing)
DOWNLOAD

Feel free to download and check it out for yourselves. Centre scan mode is definitely not as sharp as full scan, but I'd call the difference subtle.
 
morgan_moore said:
On lense sharpness is it worth considering a 2/3 lens with a 1.4 converter to get the best from this mode - such lenses are, I guess, designed to have very high lines per inch over a small projected image circle
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I used to do this with an Abacus and Fuji 4.5 2/3 zoom..saving to buy the CN7 ! its not that good TBH.. and those lenses are designed for 3CCD sensors.. it works but far from ideal.. but agreed alot of doc,s content is king..
 
Ben Scott said:
allenfacemire said:
In an FS7 1080p image the camera is using the entire 4k sensor and downsampling that to 1080p, meaning each pixel (and grain of noise) is made a lot smaller in the process. Hence sharper images and less noise.

Centre crop basically uses a smaller than 1080p sliver of that sensor and then blows it up to 1080p, increasing the size of the pixel and noise.

Not really sure what you mean about using more of the lens as you open it up, and the more light to you let in from various angles, the softer an image is. That's why we squint with our eyes to see something sharply.

In summary, it's not an anomaly but the simple results of making a big thing smaller vs making a small thing bigger.
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Well, in conventional still camera or even motion picture camera lenses, the physics of grinding lenses results in the outer edges of a lens being less perfect than the smaller area in the mid section of the glass. This was one of the big challenges with the Hubble telescope for example. The more open the iris, the more of the surface area of the lens is used until eventually the entire surface of the glass is exposed to light via the wide open iris blades so that even the less perfect section outer edges of the lens is being used, thus a slightly softer image. Hence the opposite when stopping down. As you stop down you start using less and less of the lens surface until you are left with the very sharpest or more perfect portion of the lens. Lots of still lenses with manual apertures actually had a different color for stops between f5.6-f11. Depth of field starts to get wider the more you stop down because of the lens aberration just mentioned. Basically the sweet spot of any or at least most lenses has always been 5.6, kind of right in the center of the iris range.
That's my belief all these years and the ASC Manual cooperates this with their depth of focus chart.
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