Proper backfocus with Blade

T

truelife

Well-known member
Did my first interviews with the Blade yesterday but was confused on how to get proper backfocus settings. Focused on grain with EX-1, then
adjusted Nikon 85mm f1.4 with follow focus. However, never got an image that was truly sharp to my eye or the Nebtek 7" monitor. See example
here. Suggestions?

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The manual states that focusing on the GG so that you can see the grain isn't the best method. I have to agree. Here's what I found works very well:

Assuming that the 35mm lens colimation is correctly adjusted.

1. Zoom in on to the GG to get the proper framing.

2. Open the camera's iris wide open, stop down the 35mm lens, point it toward a bright light and then focus on the grain. (this is just a starting point)

3. I open the 35mm lens to it's sweet spot (around f4, typically) and close down the camera to it's sweet spot (again f4 for my camera). and then set the 35mm focus to infinity.

4. I adjust the camera's focus ring until the picture is sharp. It's typically a small adjustment but makes the difference between a sharp final image and soft image.
 
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First - you are not describing back focus - that is 35mm lens on the screen within the adapter. You are talking about focusing the video camera on the adapter screen.
Personally I dislike all the focusing methods on the grain of the adapter screen as it is not your final image.
If you have the time and space (and in an interview you do) blow up a focus chart and mount it on a piece of foam core - 2 to 4' wide.
Bring it with you to the shoot and mount in front of the camera. focus 35mmm lens first then video camera and go back & forth till you have the best focus on the chart and the best compromise between center focusing and corners for your shot. This is foolproof and 100% accurate. It helps to have a good monitor of course.

You should always do this and any other focus adjustments whether using a chart or another method using the grain with the video camera lens iris wide open. So even in the method above I think you should always have your video iris wide open.

Lenny Levy
 
here's how i do it.

setup camera/adatper - turn them both on! - plug into good HD monitor. i use a program on the computer that gives me 200% so i can see the focus properly :)
zoom into desired frame size. then lock off the zoom with gaffa tape.
focus your 35mm lens (wide open) onto something with fine detail like a newspaper.
open video camera's iris till it's wide open. and close down the 35mm lens to compensate.
then pick and area half way in between the center and the edge and focus your video camera as well as you can by going back and forth. then lock it off with gaff. but be careful not to nock the ring.... i like to use several small pieces to lock it off initially then a couple of big pieces for safety.

that process is basically the same as lenny's. it gets the sharpest image possible.
 
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I am a little confused here. For reference - I used to have an M2 and my SGBlade in on the way.

How do you focus the 35mm lens without first focusing the video lens. According to jenningsp he focuses the lens but if the video lens is way off, how do you tell that 35 lens is indeed in focus?
 
Jennings ,
That sounds like a pretty good method if you have no chart.

Re the last question. As I mentioned in my post. You just go back and forth between 35mm lens and video lens - you'll get it very quickly, its not brain surgery.
 
Hi guys,
it's a different tip for me...
I use the macro on my JVC GY-HD200E to focus on the grain of the roto razor, than turn on the adapter at maximum speed, to avoid flickering, (focus lenses at infinity on a clear surface like a wall) and that's all!!!
It's fast, safe and easy.

Matt
 
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