Couldn't get the focus right, teach me please

highpeak · Mar 30, 2006

I followed the instructions to tilt the front and back of the camera, try to get everything in focus. The picture I got is worse than the one without tilt, they were all shot at same F stop. I just can't figure out why.

The set up is 150mm lens on 4X5 camera, subject about 1.5 meter away from the camera. camera is a little higher than the subject. I am really puzzled, isn't the tilting suppose to give a wide plane of focus?

Please let me know what I did wrong, thanks. Alex

the landscape picture is w/o tilt, the other one with tilt.

Dave Parker · Mar 30, 2006

What f/stop did you shoot this at?

Dave

Donald Miller · Mar 30, 2006

I see two still lifes. I don't see a landscape photo.

The set up for the camera should have the back perpendicular to the vase and flower.

If you have insufficient front fall then the camera bed should be tilted downward and the back returned to perpendicular to the vase and flower. The front should be parallel to the back unless you want additional depth of field in which case the lens standard should be tilted.

If you tilt the back you will induce distortion. Sometimes that is desireable. In this case, I would wonder about inducing distortion.

If you are shooting with the camera positioned directly in front of the vase and flower there is no need for swings or shifts. Those would only be used if your camera was to the side of the main object in the exposure or if you had more objects to the side of the main object in the scene and not on the same plane as the vase and flower and required more depth of field.

Beyond that you should be focusing on the ground glass with a loupe. If the image is sharp on the ground glass then the exposure should be sharp.

One additional thing. You failed to mention the Fstop at which the exposure was taken. If you stopped the lens down beyond F 32 on 4X5 you will probably experience defraction if you print this at much of an enlargement

ras351 · Mar 31, 2006

Tilting the camera doesn't increase the depth of field - it changes the plane of focus which under certain circumstances can help encompass those features in a picture which you would like to have in sharp(ish) focus. This is most useful with things such as a flat landscape where you can modify the focal plane to closely parallel the landscape (rather than being normal to it) and hence keep most of the landscape in focus. The further away the object from the intersection line of the three planes (film, lens, focal), the greater the depth of field given the distance to the focal plane.

In the case of your flower and vase most people would not use tilts unless they wanted the flower to be in focus and the bottom of the vase out of focus. Rather than having me rehash things which others have already written do a google search for Scheimpflug.

Roger.

roteague · Mar 31, 2006

Alex,

You have the right idea, but in this case you really didn't need any tilts. If you want to learn about using tilts, you would be better served taking the camera out to shoot a landscape, then you can practice with the tilts. In the portrait version of the image, it looks like you really used too much tilt.

highpeak · Mar 31, 2006

Satinsnow said:
What f/stop did you shoot this at?

Dave

Dave, the f stop I used is 22 and your ground glass is wonderful on the camera.

Thanks all for the help. I am confused with the DOF and plane of focus. But, on the slide the back of the table is not very sharp in the landscape version, isn't F22 should've produce enough DOF to cover that?

In the portrait version, I did find where the plane of focus is, it's between the letter RDPIII and a group of numbers on top of RDPIII.

Robert is right, I need to go out and shoot more films.

Take care,

Alex

Dave Parker · Mar 31, 2006

Alex,

Have you picked up any of the books that use illustraitive photos to show what the effect of tilt and swing are yet?

It helps if you can visualize what each movement of the camera does, the cause and effect of the images can help alot...I probably would have stopped down a bit more, when I was learning LF shooting, I always set up very bright lights, so I could see the effect of the tilt and swings on the ground glass easy...

But that said, it looks like your on the way, thanks for the compliment, glad the glass works for you.

Dave

ras351 · Mar 31, 2006

One way to think of it which may help is to think of an imaginary pane of glass which you place in your picture. In a camera without movements this would be parallel to the film but it doesn't have to be so with a view camera which is where you can use tilts and swings. Everything which is located on this pane of glass is in sharp focus. The Scheimpflug line is an imaginary line which is the intersection of this pane of glass (object/focal plane), the film plane and the lens plane. The further away from this intersection line the greater the depth of field for a given aperture so you can think of this as a wedge radiating out with the pane of glass in its centre. Subject to your circle of confusion everything within this wedge is considered in focus and everything outside is considered out of focus however you still need to be aware that the further away from the pane of glass the less in focus the object. You can increase the angle of this wedge by stopping down the lens further. I won't mention diffraction just yet as I've probably confused you enough.

Roger.

roteague · Mar 31, 2006

highpeak said:
Robert is right, I need to go out and shoot more films.

You don't necessarily need to shoot more film, just spend more time on the compositions you have setup, until it becomes second nature. Even taking the camera outside, setting up different compositions and trying different means of focusing and camera movements, without shooting film will help.

Also, get yourself a copy of Steve Simmons book "View Camera" and a copy of Jack Dykinga's "Large Format Nature Photography".

Wilbur Wong · Mar 31, 2006

The other posters are correct to direct you to some books on the subject. As a radical fast study of the subject of "tilting" or "scheimflug" I suggest doing this:

Set up a bunch of objects across your dining table scattered all across the surface. With your camera on a tripod a foot or two from one end of the table, and maybe a foot above the surface, focus your camera on an object near the center of the table. Not the furthest or the nearest.

Now tilt the lens forward or downward, and then maybe refocus with the lens-ground glass spacing or rack. (Alternatively tilt the ground glass away from vertical) and refocus. If you can get everything on the table from near to far in focus at the same time, you are on the way of using your view camera!

KenM · Mar 31, 2006

There was a really good description of how to visualize the need (or lack ofneed) for tilts and swings. It's on the site somewhere, but I can't find it at the moment. Here's the quick version:

Take the elements that you want to be in focus, and mentally surround them with a box. If the box has three dimensions, where the dimensions are all 'sufficiently' large (judgement call required) then tilts and swings won't be that useful. However, if one of the dimensions is smaller than the other two, then you can use swings and tilts to increase the depth of field where you need it. If the box is veritical, then you can use swing, if the box is horizontal, you can use tilt. If the box is tilted, then you can use a combination....

Remember that tilts and/or swings don't equally increase depth of field along the plane of focus. As you get further away from the camera, the depth of field will increase - DOF is very shallow close to the camera, and increases as the distance from the camera increases. This is why tilts and swings work best with planar surfaces...

A was mentioned above, there are some good books on the topic - Steve Simmons has a good book on using the view camera - check it out from the library, and give it a good read. It's worthwhile.

GregT. · Mar 31, 2006

highpeak said:
I followed the instructions to tilt the front and back of the camera, try to get everything in focus. The picture I got is worse than the one without tilt, they were all shot at same F stop. I just can't figure out why.

Don't know what specific instructions you were following but I found Howard Bond's Focus/Check procedure in his tutorial "Check List For View Camera Users" located on Q. Tuan Luong's Large Format website to be instructional and very useful. URL to the article is http://www.largeformatphotography.info/articles/bond-checklist.html

highpeak · Mar 31, 2006

Thanks Wilbur, sounds like a lot fun.

I did get some book to read, and I plan to read them like I am preparing for the SAT.

Thanks again everyone.

Couldn't get the focus right, teach me please

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