college assignment

[Helen B]

The three classic methods of doing this with one exposure are to use a split diopter (ie half a supplementary close-up lens); to use tilt (possibly the easiest and most common method); or to use a relay lens system to create an aerial image of the distant subject in the same plane as the near subject. The latter method is fairly complicated and it has limited applicability.

Do any of those methods sound like anything that you have been taught?

Taking two exposures, one focused close and one focused far, is not totally straightforward, particularly if it is done on one piece of film with a half-frame matte. As many lenses are focused the magnification changes subtly. Therefore two images taken at very different focus points could be at two noticeably different magnifications. A simple composite would show the difference at the join.

Focus stacking software gets round this by adjusting the magnification. High-end motion picture lenses get round it by changing focal length as they are focused, so focus pulls don't look weird.

Does any of this sound like something that you may have been taught?

Good luck,
Helen

 

[Funky]

im seriously going to freak out if someone else gets it, ive been a professional photgrapher for 2 years now, and ive never come across anything like this. when he explains it on monday, ill be sure to let you all know how he does it.

Edit: we havnt really gone indepth, yet. but ill definitly do a little reading on what you just mentioned hellen =]

 

[JerryPH]

Interesting teaching method... ask the class to achieve a goal and then teach them how to do it a week later... LOL!

 

[fstopusa]

Hey, I just had a thought. Time lapse married with light painting.

In a completely or as completely dark setting:

• Open the shutter focus on one subject in foreground and hit it with a flash/strobe
• Second area out of focus and light it up with flash/strobe
• Third area in focus and light it with flash/strobe

Only the areas you have lit will show in the photo.

 

[Helen B]

You would just have to watch the change in magnification at the joins - perhaps by keeping that area dark, or ensuring that it has no detail. The alternative to light painting is to use a partial matte, as I mentioned in my previous post.

Best,
Helen

 

[Jon, The Elder]

does anyone happen to have any idea how to focus on something in the foreground and background at the same time, while getting the middle of the frame to be out of focus?

As a single exposure it is optically not possible. However, the opposite is quite easy to accomplish.

 

[JerryPH]

As a single exposure it is optically not possible. However, the opposite is quite easy to accomplish.

Thats what I was thinking... did he misunderstand? I cannot see the need for 2 planes being clear and the center being out of focus, but who knows.

 

[Helen B]

As I mentioned in my first post in this thread, it is possible with a single exposure if you use tilt, apart from methods like using a split diopter.

Imagine the branches of a tree in the upper part of the frame, with a field below. If the lens is tilted upwards the plane of focus will extend from close objects in the top of the frame to distant objects at the bottom of the frame. You could arrange it so that the foreground branches are in focus, the middle ground of the field is out of focus and the more distant part of the field is back in focus.

Best,
Helen

 

[JerryPH]

Makes more sense to me now, Helen, thanks.

A 2 second google gave me this, and I believe the answer to the OP's question.


http://tvtropes.org/pmwiki/pmwiki.php/Main/SplitDiopter

 

[Helen B]

Hoya and Cokin call them 'split field': link.

Best,
Helen

 

[Foques]

Jerry, you are right.. In the book he says about foreground and background being in focus simultaneously. shy of the middle part being out of focus.. my bad.

 

[Mary-Beth]

Split exposure on one frame. Assuming you're shooting 'down', out of the horizontal plane: focus and shoot the foreground subject, with the top half of the lens covered. Then focus and shoot the background subject, with the bottom half of the lens covered. F/5.6. The two out-of-DoF fields should smoothly merge in the middle.

 

[Helen B]

That's the method I referred to as taking two exposures, one focused close and one focused far,... done on one piece of film with a half-frame matte.

As I mentioned, there can be a mismatch at the join because of the slight change in magnification of the middle ground, even if you match the degree of blur. It will, therefore, be a good idea to have the join in a fairly featureless area.

The mask or matte itself is usually placed in something like a compendium shade, so the distance from the front element of the lens can be controlled. In the movies it's called a matte box, even though many times it is used without a matte.

You use two mattes, sliding along rails. The mattes can be cut to a curved line or a straight line - they just have to match. The first matte is placed as required, and the first shot taken. Then the second matte is slid up against the first matte, and the first matte removed. The second exposure is made.

Good luck,
Helen