Soft Image

[Paul Leeming]

The NULL lens works great, it's a very short focal length with a narrow FOV and permanent infinity focus. It gets a lot of mixed reviews, but I think that comes back to two things; people are unsure of what to point it at and what to look for to verify focus. When setting the back focus on RED with a proper tool like the NULL, if you're doing it right, the image will seem to pop into focus when it's right.

One thing to note when using the NULL (awesome product), pay attention that you don't put your mount back out of alignment with the simple act of tightening the two mount screws. Tighten them slowly (one at a time) while watching the monitor to make sure you don't cause it to slip back out of focus. And once tightened, verify that you're still in focus (if using the LCD make sure you're using the expanded zoom mode (right button) for actual 1:1 focus check).

HTH

Paul

 

[Eric Rainey]

If all my marks on my nikon lenses(fixed/primes) are a little off from their distance marks and each lense hits focus on a different mark in relation to each other then is there a way to get them all to nail the same distance marks? Pay to have them all alligned? If so, is it expensive?

 

[Jeff Kilgroe]

I am not zooming, I am using a brand new Toikina 11-16 and a new Nikon 18-200 set to 18, I have measured the distance from a simple chart to the camera's film plane, set that distance on the lens and set back focus on the Red until sharp. Both these lenses have the same back focus setting on the Red. I am using the button to zoom for focus.

But do you know if the distance marks you're using on the lenses are actually right? I'm just saying that if you're having soft image issues, which indeed seem to be back focus issues based on your description, you may need to find a more accurate method to set your mount with. Just sayin' I understand that you're trying to use what you have, but there are times that what you have may not be good enough or even the right tool for the job.

Ideally the lenses should be focused at infinity and focused on a distant object rather than trying on a chart at an arbitrary close distance.

Where do you have your aperture set when doing this? At what distance is the chart?

If you had a choice to shoot a scene that you need to frame people with a frame width of say 16 ft, would you prefer use a wide angle, or space providing use a longer focal length and move back.

That is entirely subjective. It all depends on the look you are going for. For portraits or generally shooting people, I find it better to avoid wide focal lengths and the distortion that comes with them. However, I do love shooting with wide focal lengths for that particular look they create. It's all about the look.

One thing to note when using the NULL (awesome product), pay attention that you don't put your mount back out of alignment with the simple act of tightening the two mount screws. Tighten them slowly (one at a time) while watching the monitor to make sure you don't cause it to slip back out of focus. And once tightened, verify that you're still in focus (if using the LCD make sure you're using the expanded zoom mode (right button) for actual 1:1 focus check).

Good advice, Paul. However it should be noted that this does not apply only to the NULL. But to any lens or other device you may have hanging off your mount while doing the adjustments. I have the best luck with keeping the mount in proper alignment by not over-loosening the screws to begin with and then doing as you say, tighten one, then the other. There are times when the mount can slip from where you want it just when you tighten the screws if you're not watching carefully.

If all my marks on my nikon lenses(fixed/primes) are a little off from their distance marks and each lense hits focus on a different mark in relation to each other then is there a way to get them all to nail the same distance marks? Pay to have them all alligned? If so, is it expensive?

Technically yes. Although, it depends on each lens design and how serviceable they are. With still lenses, their manufacturing tolerances are usually within range of accepted specs, but the marks are never specifically calibrated. Sometimes the lenses can be tweaked, sometimes they need to be re-marked with calibrated markings. Yes, it can be expensive. Especially in relation to the original cost of most still lenses.

http://www.ducloslenses.com

 

[Paul Harding]

Ok. Thanks for all the input, I have come to the conclusion that I won't get better images at that angle and distance, it may be I was expecting to much from the Red/lenses I have. It's good to get so much feedback from you guys, thanks Paul

 

[Larry McKee]

Paul, I have the Optitek Nikon Pro-Lock mount and this is what works for me. I mount the Tokina 11-16 and set it to 11mm. I loosen the two RED mount locking screws just enough for the mount to rotate. (Jeff is right, you don't want to loosen those screws too much - things will get wonky if you do.) I point the camera out the window at a bird house about 150 yards away and set the lens to infinity. I turn on the 1:1 view and rotate the mount until the birdhouse is in focus. Then, carefully tighten the two locking screws while watching the monitor to make sure nothing is shifting. Once I do that, all my Nikons work fine.

Don't discount the Nikon lenses. I have clients that specifically hire me because they love the look of my Nikon primes. Those lenses sure do love people.

 

[Paul Harding]

I have used that method of setting back focus, one thing I have noticed when turning the Red back focus ring is that it doesn't seem that critical when turning. What I mean is that there seems to be slow to go in and out of focus, so there seems to be a small band where the ring is in focus, it's difficult to explain. When you use some nikon lenses the manual focus is very sensitive, which is not the case on the back focus ring. I understand that the movement on the ring only moves the alinement a small amount. I say this because most of the advice on the feedback talks about the back focus, which seems really easy to do.

I have tried to put some pics up but failed to upload, also when going to upload pics I can't find the Tiff option what most people seem to use. will try again

Paul

 

[Paul Harding]

Here are 2 pics one shot D2x the other Red both shot from same distane Red was F8

 

[Stephen Williams]

I have used that method of setting back focus, one thing I have noticed when turning the Red back focus ring is that it doesn't seem that critical when turning. What I mean is that there seems to be slow to go in and out of focus, so there seems to be a small band where the ring is in focus, it's difficult to explain. When you use some nikon lenses the manual focus is very sensitive, which is not the case on the back focus ring. I understand that the movement on the ring only moves the alinement a small amount. I say this because most of the advice on the feedback talks about the back focus, which seems really easy to do.

I have tried to put some pics up but failed to upload, also when going to upload pics I can't find the Tiff option what most people seem to use. will try again

Paul

Hi,

Ideally back focus needs to be within 5 microns, thats about 1/10th of the thickness of a human hair. It's NOT easy to do properly, with lenses that move in a mount to focus it is not an issue, however with many modern lenses focus cannot be achieved if the back focus is out.

Stephen

 

[Stephen Williams]

Here are 2 pics one shot D2x the other Red both shot from same distane Red was F8

They both look out of focus, how was the D2x focused? F8 is probably past the sweet spot on the lens due to defraction.

 

[Paul Harding]

They both look out of focus, how was the D2x focused? F8 is probably past the sweet spot on the lens due to defraction.

The DX was F4 with a higher shutter speed, I have just done a lot of testing today but the results are the same, I have checked and checked the back focus, this is only an issue with wide angle and about 15 feet away from camera to subject

 

[Paul Leeming]

One further thing to note, the ring around the PL mount isn't a direct connection to the underlying flange adjustment area. So you need to keep a little pressure on it (ie. don't loosen too much) to give it grip on the flange part.

Those pictures you uploaded - are they 100% crops or is that the entire picture shrunk down?

Anyway, HTH

Paul

 

[Larry McKee]

I think what you are seeing is the difference between a camera that does the sharpening for you automatically and a camera that allows you to decide how much sharpening you want.

Here are a couple frame grabs. The first one is untouched except for size and the second one has had a touch of grading and sharpening applied. The jpgs still look soft on the web. But look sharp in the post house.

 

[Paul Harding]

the back focus was very loose as it is difficult to turn with a slight pressure on it. They are 100 % cropped tiff from redcine.

 

[Paul Harding]

I think what you are seeing is the difference between a camera that does the sharpening for you automatically and a camera that allows you to decide how much sharpening you want.

Here are a couple frame grabs. The first one is untouched except for size and the second one has had a touch of grading and sharpening applied. The jpgs still look soft on the web. But look sharp in the post house.

Larry
You are a lot closer than I am or a longer focal length If I get close I don't get the problem

Paul

 

[Stephen Williams]

Larry
You are a lot closer than I am or a longer focal length If I get close I don't get the problem

Paul

How was the Nikon focused? by eye or Auto. In any comparison test you need to use the same F stop for both.

 

[Stephen Williams]

Larry
If I get close I don't get the problem

Paul

Then it's a back focus problem........

 

[joshua csehak]

They both look out of focus, how was the D2x focused? F8 is probably past the sweet spot on the lens due to defraction.

Any diffraction at f8 is gonna be really slight if at all, in my experience. Usually you have to stop down to 11 or 16 to see any.

 

[Paul Harding]

I watched a video today about using the Null, in which the guy was focusing on distant objects, while using the null. I done the same thing with my Tokina 11-16 and it worked, I have a much sharper image, so problem solved.


Thanks for all the input.

Paul

 

[Stephen Williams]

I watched a video today about using the Null, in which the guy was focusing on distant objects, while using the null. I done the same thing with my Tokina 11-16 and it worked, I have a much sharper image, so problem solved.


Thanks for all the input.

Paul

Back focus is most critical with a wide lens at infinity, so you should be fairly close now.

 

[Paul Harding]

I put some N D's to enable me to use wide open to focus while setting the Back Focus

Paul