Scarlett 2/3" - Action Sports? Some questions...

[Miklos Konczol]

Interesting what U said.

Is this lens would be realy 120-100 L/mm?? (hard to belive that it has better picture than a nikon pro lens) but who knows.....

for 335 Euro....

link for EU: http://www.mengelengineering.dk/products/lenses/?id=166&PHPSESSID=4623384f51ecd8a816465a919e215f49

link for USA: http://www.kowa-usa.com/frontend/proddisp.asp?co=10000349

EDIT: It is for B/W camera.

 

[Dan Hudgins]

11mm image circle for 2/3" sensors

11mm image circle for 2/3" sensors

Interesting what U said.

Is this lens would be realy 120-100 L/mm?? (hard to belive that it has better picture than a nikon pro lens) but who knows.....

for 335 Euro....

link for EU: http://www.mengelengineering.dk/products/lenses/?id=166&PHPSESSID=4623384f51ecd8a816465a919e215f49

link for USA: http://www.kowa-usa.com/frontend/proddisp.asp?co=10000349

EDIT: It is for B/W camera.

I noticed what you saw about the B/W camera, I think that is there for two reasons, the OLPF used on a color camera would reduce the lp/mm value, and using a lens that sharp on a color camera without an OLPF would give some chroma moire issues. The lens is not corrected for the thickness of the OLPF, but cine camera lenses are not corrected as well.

So that gets into the sticky issue of the "Plate Effect" on all lenses not corrected for a plate of glass or whatever behind the lens...

As to if newer DSLR lenses are corrected for the thickness of the OLPF used in the Scarlet, maybe/maybe not? We do not know how thick the OLPF will be in Scarlet yet. The OLPF will reduce the resolution with most lenses, that is its job, that is how it reduces chroma moire and aliasing. The resolution will fall more for fast lenses, f/0.95 and f/1.2, than for slow lenses.

Since the sensor's active area is only about 10mm wide a 5mm lens is not super wide, you would need at least a 5mm lens to shoot with. The jump from 5mm to 12mm would be too great, so you would want both an 8mm and 12mm. A 12mm is medium wide, a 25mm is a little longer than a "normal" lens. 50mm is longer than a 75mm would be on a 35mm movie camera, and 75mm is about as long as you would use for normal shooting on 2/3" format.

It is easer to get high resolutions with a smaller image circle, but the building of the lens makes it harder for the improvement to hold the ratio, so as the sensor gets smaller it gets harder to keep the lens resolution in proportion to the image width.

The Megapixel lenses should be color corrected for 450nm to 650nm or more. Some video lenses are color corrected form blue to IR, but it is best to filter the UV and IR out with a filter in front of the lens so that you do not get off color halos around the image points.

The problem with IR and wide angle lenses is that the IR filters that use interference do not work at steep angles, so for wide angle lenses you need a behind the lens IR filter or a "green glass" type IR filter that is not as sharp cutoff.

The Bayer filter's Blue (and sometimes Green) sensors can pick up far Red and IR so it is best to filter out colors longer than about 650nm to get the sharpest results, along with UV, since the UV and IR focus point is not the same as for visual colors.

I was looking at some 2/3" lenses vs. some SLR lenses on the same C mount camera with adapters yesterday, and yes the machine vision lenses should come out about two or three times as sharp to shoot with on the Scarlet as a SLR or DSLR lens, because they cover a smaller image area they can be optimised to put smaller image points in that smaller area.

Maybe you can find the MTF curves for the Nikon pro lens you are looking into, there are some good SLR/DSLR lenses but very few better than 60lp/mm to 85lp/mm since color film cannot resolve much more than that, and if the lens is too sharp a digital camera will show more chroma moire and aliasing, so there was little need for sharper lenses.

Leica seems to have made some super sharp tele lenses for the US millitary to shoot spy photos with, but those cameras used microfilm to get more resolution than color film could resolve.

People have been talking about using Super16 lenses in PL mount, but so far there has not been a link posted to the MTF curves for those. Being made for color film, I do not see why they would have been made better than 120lp/mm or even 90lp/mm at 50% MTF, maybe someone can talk more about that, someone said such lenses go for $10000 each!

Small Linos lenses were used on Slumdog Millionaire (2008) using the 2/3" sensor SI-2K mini digital cinema camera,

http://www.linos.com/pages/no_cache...ine-vision-lenses/?sid=13516&cHash=c8b0deb937

 

[Brant Williams]

Antoine, Dan and David,

Thanks for the thoughtful and informative comments.

You are definitely right about the bias against a fixed lens. That may be a good way to go for my application. I guess I will just cool my jets, be patient, and wait for the cameras to get out so we can have some real world feedback!

 

[Petr Dvorak]

Just wonder how these good 100lpmm c-mount lenses handle in shooting. How sturdy they are built? How many blades use, 3 or more? etc. etc

 

[Dan Hudgins]

Plastic threads!

Plastic threads!

Just wonder how these good 100lpmm c-mount lenses handle in shooting. How sturdy they are built? How many blades use, 3 or more? etc. etc

Many of the newer Machine Vision lenses have lock finger screws to lock the iris, most do not have click stops and are not marked for every stop, some have no marks at ALL, just open-close and near-far.

Opticaly some of these type lenses seem quite good for the price, but the plastic ones can have "sticky" focus that might drive you nuts unless you leave the lens locked for hyperfocal.

The number of blades seems to vary, I don't see that spec in the Mfg's pdf files, so you need to look into the lens to count them...

Since I am mostly looking into this for no-budget feature making, I ask myself how many times will the lens be used, i.e. how many shots, for the widest and longest lenses i.e. <5mm and >50mm maybe 10 shots, so it is not such a big thing if the lens is a little wanky. For the lenses you use all the time like the 8mm, 12mm, 16mm and 25mm you would want ones strong enough you could put focus gears on them, and be able to lock the iris, since without click-stops it is easy to bump the iris ring while reaching for the focus.

Lenses that are marked for distance are almost off too much for using the numbers by tape at 3K resolution, so I hope Scarlet has some kind of back-focus adjustment to get INF set right, this is most important for zoom lenses since they will not track focus while being zoomed if the backfocus is off just a small amount. The backfocus tolerance for shooting 3K will be about 1/4 that for 16mm film shooting, so the mount needs to be very good.

About the f/1.4 and faster lenses, the OLPF will be an issue with the small pixels in the 3K Scarlet maybe more than 2K mode on the REDONE since the extra blur at large stops could blur more than 2 pixels wide making the resolution fall off at large stops. The red people have not been talking about what adjustments they are working on for the OLPF in Scarlet, since on the 2/3" format you need faster lenses to make up for the S/N ratio being lower, so sharpness at large stops is important, also people will be using larger stops to get less deep DOF.