Adjusting the DOF

berlinfool

berlinfool

Well-known member
I just wanted to know if this is the correct way to adjust the DOF:
I choose the aperture on my Nikkor lens in front of the adapter and then adjust the expsoure within the camera, right?
 
Kind of... you can get into issues depending on the type of adapter you use with your method

Spinning GG on an adapter (m2) will allow a greater depth of field using the same mm lens because you have the ability to stop the lens down more than a vibrating GG like the Brevas. The grain on the GG shows up sooner on a vibrating adapter.

I try to set my cam to f4.8 or 5.6 with no in camera NDs engaged ever and then use ND filters on the SLR lens as needed to achieve the DOF and exposure I need for the shot I want to get
 
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Uh - sounds more complicated than I thought.
I have the Letus Extreme.
The grain on the GG shows up sooner on a vibrating adapter.
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So how far can I stop down my SLR lens?
no in camera NDs engaged ever
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Why can't I use the in camera NDs?
I try to set my cam to f4.8 or 5.6
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Why did you decide on those numbers?

Thanks
 
yes. In most cases this holds true, even without the adapter.

An adapter's GG usually begin showing when you close down the iris on your " SLR lens". The numbers vary depending on the GG. f5.6 is sometimes the optimum depending on your adapter gg AND slr lens. Lets say a nikon 50mm f1.4 can be closed down to f5.6 with acceptable results on a spinner. An 85mm f2.8 can be closed down to f4 because this has a smaller rear elements than the latter example.

But as you can see, based on these samples, there are different variables which comes to play. YOU can best decide on whats acceptable and pleasing to YOUR eye in the end by testing out.

A lot of users have come to varying exact figures but similar in principle, and this is because of different characterestics of camera, adapter and slr lens.

In my tests, you can achieve sharper edges if you close down your cam iris. If its outdoor and bright and you can close down to f8 or f11 then this is best. but if your corners dont require to be sharp then you can open up your iris to 5.6 or even 2.8. But these really soften the corners in most adapter tests ive seen.

I think i posted those chart tests here somewhere. I forgot where.


Ted
 
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berlinfool said:
I just wanted to know if this is the correct way to adjust the DOF:
I choose the aperture on my Nikkor lens in front of the adapter and then adjust the expsoure within the camera, right?
Click to expand...
you're essentially correct. Choose the stop on the stills lens that will give you the depth of field that you are looking for ( shallow or very shallow but that's why you're using the adapter ), then adjust your video camera to get proper exposure. Feel free to use the in-camera ND's although sometimes they can be too heavy. I also have a set of ND,s for the stills lens but only occasionally pull them out.
Try to stay below 5.6 on the still lense and try to get to about F 4.0 on the hvx although the camera setting is not as crucial.
Shane.
 
I get great results with my In camera ND....I go wide open on my F1.8 50mm and wide open on my DVX and ad ND....Great results and very shallow DOF.
 
Hi Berlinfool

A couple of answers for you... most if not all of them are just what I do based on tests and are in now way rules.


Keeping the camera at f4-f56 - all lenses work their best stopped down a little... through tests I found that this range is what best for the image I like to see out of my camera adapter or not. I keep it stopped there, if I can, so I have the sharpest frame of the Letus' ground glass.

I've found that nd-ing the slr lens makes for the picture I want to see. That is to say minimizing the light hitting the gg element.

The hardest thing you'll find with the adapter is getting enough dof rather than shallow dof.

I found the letus works best at f4-f5.6 but if I shoot sky for example and go higher I start to see the gg. Thus nd's and polas and gradient nd's.

As for the in camera nd's.... just a thing I do.... I'm sure the cams nd's are fine.

In a nutshell, test... do a bunch of tests and find what works for the picture you want to see.
 
trudd said:
Yeah, why not use the In-cam NDs? I thought Barry_Green okay'd that a long time ago!
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Mostly for control.

Having a full kit of high quality nd's is what I prefer. I can get closer to the optimum nd I'm looking for rather than the two settings chosen for my by someone at Panasonic.
 
I used the internal NDs on my shoot today and everything looks great.
I only wished that there were more settings then just two. I couldn't always use the f-stop I wanted to use.
 
berlinfool said:
I used the internal NDs on my shoot today and everything looks great.
I only wished that there were more settings then just two. I couldn't always use the f-stop I wanted to use.
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That's why you would carry a set of external ND's (in addition to or instead of the internals )- to get the stop and therefore depth of field that you want.
Shane.
 
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