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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Is there a 2k mode "soft image" problem or not?

Hehe, I knew I'd get a quick response to that post. Precisely what I was looking for. Re-assurance.

Cheers mate.
 
Jannard said:
You can rule sensor inconsistencies out... lenses, back-focus, bad focus or operator error. But not sensor inconsistencies. There are none at 4K... so there are none at 2K.

Jim
Click to expand...

Hi,

Probably lenses, only the latest S16mm prime lenses from Zeiss & Cooke are really sharp. I don't think any S16 Zooms are 'really good'. As the sensor size gets smaller the quality of lenses has to increase several fold, thats why the Zeiss digiprimes are rather expensive.

Stephen
 
hi, can you explain ?

hi, can you explain ?

deadmike said:
yes, backfocus is an issue with primes as well.
Click to expand...

I'm a rather inexperienced wildlife movie make, mostly using the very kind of prime still lenses I see on your avatar ! To me, given you focus by eye with the evf, when you nail focus, it means you see what the sensor sees... so how can you have a back focus issue ?? I'm going Red precisely for wide angle shots, so I'd love to know how to check back focus with a prime still, say 17 mm... Same routine as with a zoom : the chart and all the stuff ?Thanks for answering, regards, Denis
 
buhot said:
I'm a rather inexperienced wildlife movie make, mostly using the very kind of prime still lenses I see on your avatar ! To me, given you focus by eye with the evf, when you nail focus, it means you see what the sensor sees... so how can you have a back focus issue ?? I'm going Red precisely for wide angle shots, so I'd love to know how to check back focus with a prime still, say 17 mm... Same routine as with a zoom : the chart and all the stuff ?Thanks for answering, regards, Denis
Click to expand...

Hi,

If the back focus is out you may not be able to reach infinity using a simple lens. With a modern lens with floating elements you may not get any focus at all.

You should always use a properly collimated wide lens when setting backfocus, it's more critical. There are several threads outlining how to set back focus.

Stephen
 
Yes you could think you "nail" focus with the Evf, but if your back focus is improperly set you won't know what the maximum sharpness could be, you may not be able to focus to infinity, and your focus scale will be off. Search the forum for the best ways to adjust back focus.
 
back focus with wide lens

back focus with wide lens

thank you all !
 
one thing, though

one thing, though

breizo said:
Salut Denis
That link could help you to do your back focus properly.
http://www.youtube.com/results?search_query=nikon+mount+red+camera&search_type=&aq=o

And BTW We did some 120 FPS With Nikon lense without that softness issue.
http://www.reduser.net/forum/showthread.php?t=15514&page=2
last images #15
Click to expand...


Hi, thanks again...saw your stills.. sharp as hell... I've been through the forum. Trouble is : nikon lenses (all dslr lenses, in fact), never have an accurate meter scale. If if can't trust my eyes (and a chart), which I need to check back focus, how can I do it ? With zoom lenses, you usually zoom up, focus, then down, focus again and through the process again until you're in focus all the way down your focal length... But here again, you use your eye to check you'e in focus...any clue ? Denis
 
Denis,
use the wider zoom lense you have (better to use a new one too) open the ring lense at the max and use ND filter if needed. You can also use a bigger screen connect to the camera for a more accurate focusing.
Then control your chart in redcine at 1/1 view.
When focusing seems ok, fixe the back focus ring (carefull when you do that, you could move your back focus when screwing), and test your other lenses. I know it's a pain in the +*^! but when your back focus will be accurate, I think you'll be ok for a while.
Brice
 
Guys - is it just me or did nobody taken in the fact that we are dealing with Bayer CMOS sensor? According to Graeme the Mysterium resolves about 78% of its RAW resolution. So when You shoot a 2K-RAW You are only getting resolved 1598 px (or 1.56K)... This in my opinion is the main reason why the 2K is little "soft"...

Try shooting 3K (which resolves 2.34K) and scale it down to 2K. Then compare it to the 2K mode...

Any HD (true 1920x1080) camera with 3xCCD or 3xCMOS sensors will look sharper then 2K-RAW single CMOS. This is common sense...

Just my two pesos... :D
 
Peter Majtan said:
Try shooting 3K (which resolves 2.34K) and scale it down to 2K. Then compare it to the 2K mode...

Any HD (true 1920x1080) camera with 3xCCD or 3xCMOS sensors will look sharper then 2K-RAW single CMOS. This is common sense...

Just my two pesos... :D
Click to expand...

Hi,

Scarlet will be very useful to many I think.

Stephen
 
Especially being able to handle 3K at 180 FPS. Red One tops out at 60 FPS for 3K... I bet You anything that EPIC will handle 4K at 120 FPS minimum... :)

For me the cross-over between video and film was the difference in frame rates, not the higher resolution - which was the deciding factor for me to buy two Varicams...

Shooting 4K-RAW sure is great. But shooting 4K-RAW at up to 120 FPS would be a lot better... :D
 
Peter Majtan said:
Any HD (true 1920x1080) camera with 3xCCD or 3xCMOS sensors will look sharper then 2K-RAW single CMOS.
Click to expand...

If they have higher resolution (and many of them do), it's only because the manufacturer didn't bother to design it correctly with a very expensive anti-alias filter. Such images are easily contaminated with nasty aliases and moire: you see it all the time in video camera output.

RED could have saved a lot of time and money and just left out the anti-alias filter. Then in 2K mode with an aggressive debayer it would have the same luma (still less chroma) resolution as any 1080p camera. But it would have the same aliased look that most video cameras have already.

Granted, many people actually prefer aliased images. I don't know what's wrong with them, but hopefully the new RED Ranch will include a rehabilitation center for those poor, backwards folk. ;-)

Furthermore, it's important to remember the importance of the recording system. The EX-1, for example, records 35 mbps mpeg-2 to RED's 288mbps REDCODE wavelet.

As to the OP, I think the lens is the most likely limiting factor. Cameras with bulit-in lenses usually have an MTF designed just for their sensor.
 
Peter Majtan said:
Any HD (true 1920x1080) camera with 3xCCD or 3xCMOS sensors will look sharper then 2K-RAW single CMOS. This is common sense...
Click to expand...

This is also untrue.

3-chip cameras have their own set of optical issues dealing with prisms and alignment. A Sony Z1U and a Sony F23 are both 3-chip 1920x1080 cameras, but you sure will get vastly different actual resolution out of them. In fact, you'll get a difference between the F900R and the F23.

A single sensor camera with Bayer masking such as the RED One will lose some resolution to the Bayer patterning as well as some to the Optical Low Pass Filter.

In the end, none of these numbers matter. It is all a bunch of stats-chasing which clouds the question. The real question is what is the functional resolution of the system and that is measured in MTF (Modular Transfer Function).

I can tell you that the RED at 2K has a so-so MTF mainly due to a fairly aggressive OLPF.
 
My experience with 2k has been that I have gotten sharp looking images in low detail scenes (shallow depth of field, lots of out of focus areas, macro) and much softer looking images in high detail wide deep depth of field shots. I assumed this is due to the compression being applied and it having an easier time with lots of out of focus areas. I have not shot much 2k with 16mm lenses though.
 
Compression?

Compression?

"I assumed this is due to the compression being applied and it having an easier time with lots of out of focus areas."

2k has 4 times more bandwith than 4k, or it requires 1/4th the compression.

Is this exploited by the camera algorithms?

Is this something that can be addressed in future firmware builds?

The 2k stuff should look 4 times less compressed than similar 4k compositionns.

I have a feeling it's the effective resolution being much less that is the issue. Still, I want to know that perfectly sharp focus is possible in 2k mode.
 
i find 4k soft too. We did back focus today.. filmed a Focus chart. To my eye its soft. We used a Nikon Zeiss. when i make a 4K TIFF and open it to "actual size" shouldnt it be razor sharp? after all, its not a blow up at 100% view.
How can i upload my tiff or jpeg? the forum wont let me upload anything over few kbs..
 
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