18-50mm sharpness

[Aiden K.]

Ok, I do already know that my 18-50mm is defective and needs repair. I've already been send an RMA request from RED.

However, how sharp exactly is the RED 18-50mm supposed to be? Because I can't seen to get a sharp image from it no matter how hard I try.

I've even just recorded and spun the focus ring from one end to the other, imported the footage, framed through frame by frame until I found the MOST in focus frame, exported the 4k tiff with numerous option from RED Alert and nada, still a very unsharpened image. Not so much blurry, but not sharp. Extremely soft, compared to thumbnails others have posted on this forum.

Could this be due to the defectiveness of the lens (loose zoom rings and not holding focus through zooms) or is it just not a sharp lens, as compared to the shots from this thread: http://reduser.net/forum/showthread.php?t=33032

When I used the DRX, OLPF Comp, Debayer detail options, I get soft images to soft images with overly-sharp outlines of differet subjects, but never "true" sharp images. Basically, those options just destroy the image without sharpening the center of subjects, just the edges.

Any help on this subject would be greatly appreciated. Thanks!

 

[Jannard]

Ok, I do already know that my 18-50mm is defective and needs repair. I've already been send an RMA request from RED.

However, how sharp exactly is the RED 18-50mm supposed to be? Because I can't seen to get a sharp image from it no matter how hard I try.

I've even just recorded and spun the focus ring from one end to the other, imported the footage, framed through frame by frame until I found the MOST in focus frame, exported the 4k tiff with numerous option from RED Alert and nada, still a very unsharpened image. Not so much blurry, but not sharp. Extremely soft, compared to thumbnails others have posted on this forum.

Could this be due to the defectiveness of the lens (loose zoom rings and not holding focus through zooms) or is it just not a sharp lens, as compared to the shots from this thread: http://reduser.net/forum/showthread.php?t=33032

When I used the DRX, OLPF Comp, Debayer detail options, I get soft images to soft images with overly-sharp outlines of differet subjects, but never "true" sharp images. Basically, those options just destroy the image without sharpening the center of subjects, just the edges.

Any help on this subject would be greatly appreciated. Thanks!

The 18-50 is a sharp lens. Ché was shot with two of them. If you have checked your back focus and still have issues... contact RED (it seems like you have).

Jim

 

[Chris Burket]

The 18-50 has been discussed time and again on the forums as far as mechanical and optical comparisons if you want to search for those. But, I can tell you from personal experience by seeing many 18-50's on many different Red's, that it is a very sharp lens. We shot the fuse sequence that started off Red's last reel with one over at Plaster City. And it looked pretty darn sharp on a 4k projector.

 

[Ramesh Jai]

It's sharp. Sometimes too much for my liking but it's a sharp lens.

 

[Aiden K.]

I've attached a cropped jpg of a 4k tiff export. This shows the part of the image in which I had focused. Is this what you guys call "sharp" or am I missing something here?

 

[Stephen Williams]

What focal length & what stop? I think your FFD is off.

 

[Aiden K.]

What focal length & what stop? I think your FFD is off.

I was about 2 - 3' from the car, zoomed in to 50mm and at T5.6

 

[Stephen Williams]

I was about 2 - 3' from the car, zoomed in to 50mm and at T5.6

Should look way better, something very wrong probably FFD or somebody cleaned your lens badly!

 

[Aiden K.]

Here is another shot, I am 7" away from the subject, T3, 50mm

 

[Graeme Nattress]

http://www.cinematography.net/natress-red-res.html shows resolution tests done on red with the 18-50mm. Problem with shooting objects is that you're seeing shallow DOF which means only a very small plane of focus is actually sharp.

Graeme

 

[Stephen Williams]

Here is another shot, I am 7" away from the subject, T3, 50mm

That shot looks OK to me, just minimal DOF which is what everybody seems to be after today. Please make a test at infinity

 

[Aiden K.]

I will take an infinity shot tomorrow morning.

 

[N SPEN]

Aiden, is that from a Grass Valley Infinity? .. Oh infinity on the lens!

 

[Maz Mawlawi]

Funny you mentioned this Aiden.....We get similar results with our 18-50....I thought that was all I could expect from it... are other people saying that the image should be sharper than this?...because in this case ours needs repaired as well...