Vertical Perspective Correction on MF, Help!

I am doing a commercial photography for a furniture company. Upon seeing my

proofs, they directly reject one photo (attached) because they think the

vertical distortion is too much. They show me their competitor's photo. For

similar product and arrangement, the vertical persepective converging lines

still exist but it is minimal. I draw a line to show you where the converging

vertical lines they expect.

 

I shoot this using Nikon DSLR with 17-35/2.8.

 

So I heard that MF has built-in perspective correction. So i went to a dealer,

get this Hasselblad H1 with aptus digital back with 80 mm haselblad lens. I

test the MF on the site. Of course, I bring along my DLSR. To my disbelief,

upon reviewing images from both camera, MF doesn't make significant

improvement. There is slight improvement but I have to examine the image

carefully. At glance, both images just are the same.

 

Please verify if my technique wrong? Is there something I don;t know about MF?

Is MF is the perfect camera for this kinda job (architectural and others with

critical vertical lines)?

 

What are my options?

1. I can't use view camera (larget format).

2. No budget for expensive PC lens. If there is, i don't even know where to

get one. Very rare item in my country.

3. Studio is limitted space, i can back up more than 15 feet from the set-up

configuration.

 

Any ideas and suggestion are welcome. Thanks!

 

Ed<div></div>

A medium format camera where the lens is fixed parallel to the film plane and central to the center of the frame is going to have the same perspective issues as a smaller format camera with the same lens/film-sensor configuration. There are perspective correction lenses for medium format cameras, but they have been few and far between over the years and are very expensive ($4000 new?). It looks as though you're going to need a lot of perspective correction. If you want to do it in the camera, I would say that you'd need a view camera and lens to cover 4x5, then capture using a medium format back (since your lens will be shifted so much that it might no longer cover the full 4x5 frame without vignetting).

 

An alternative is post-processing in Adobe Photoshop and similar programs.

you can use photoshop or paint shop pro to fix the perspective that comes from looking down on the subject. For that picture, you'd need to get further away or use a wider lens. see attached.<div></div>

Edward, I mainly shoot architectural photography, including interiors that are similar to

yours. I agree with your client, the distortion is too much.

 

For exteriors I use a medium format digital back on a Linhof M679 for full perspective

control. For interiors this set up is sometimes too bulky. Then I use a either the same

medium format digital back on a Hasselblad Flexbody, or a Canon full frame DSLR with the

Canon 24mm or 45mm Tilt and Shift lenses.

 

You have two options. Get the Canon system (it's becoming a standard system for interior

photographers because of the Tilt & Shift lenses), or use perspective controls in

Photoshop. This second choice will reduce the quality slightly, and it doesn't perfectly

correct the perspective (it makes the product look slightly flatter or squatter) but it's the

most economical option.

Edward, here's a quick correction in Photoshop to bring your shot to the perspective

requested by your client.

I don't know from where you have the impression that medium format in some way corrects perspective. Thats not right at all for MF, for 35mm, for DSLR. To correct perspective in shooting you need a camera with movements or a perspective correcting lens. There are a very few medium format cameras which offer some movements. The vast majority don't.

 

I'd try the Image/Transform options in Photoshop Elements or similar which will open up a variety of tools to move you in the direction you need. There is likely to be some loss of quality and its best not to be too extreme.

 

There is of course a trade-off between height, distance and the apparent distortion produced by perspective, and if you can't use the right equipment and need to re-shoot then I'd suggest you'd be best to involve the client in that trade-off on site so he knows what he's getting.

A medium format camera is by no ways the best solution. I don't know who told you that.<br>

Your problem is not only to be able to correct the perspective by shifting the lens, but also to control the depth of field with some tilts. (Note that I don't say "increase the D.o.F.", but only control where you will have the in-focus plane).<br>

The only <u>real</u> way to have correct perspectives is to have the film plane parallel to the subject plane.<br>

Most medium format cameras are limited to one or two lenses with shift possibilities. Not a whole range.<br>

You have either to use a camera with a tilt-shift lens, or a camera which allows itself tilts and shifts. I think of course to large format cameras.<br>

A large format camera has tilt ans shift movements <u>on the camera</u> not on the lens. Thus you can use the focal length which corresponds the best to your 15 ft back up.<br>

When I say "Large format" I don't mean that you will have to produce a 4x5 in. negative. You can use a LF camera with 120 film in 4 1/2x6 to 6x12 format, or even a 135 film or a digital back.<br>

A solution would be to rent a view camera with a digital back and the appropriate lens.<br>

For the equipment that is available to you, just use the widest lens you can rent. If using the Hasselblad, use a 50mm, 40mm, or the Superwide-C with 38mm Biogon. If using the Nikon, go as wide as you can--or else get a 28mm PC-Nikkor even if you have to order it from out of the country.

 

Keep the camera back as close to vertical as you can. For the shot you posted, frame the furniture at the bottom of the frame to avoid angling the camera down too much. then crop out the top section of the frame when printing.

 

Finally, use photoshop as David suggested to further reduce the convergence. That will result in sacrificing some of the left & right edges. The use of a wide angle lens should help to leave enough of a margin around the subject, so you won't lose too much when you crop.

Hey guys, thanks for all the comments and quick fix on my photo. I will find to use photoshop as much as i can and see they want to accept it. I understand the angle is way too extreme for a just quick-fix. Because if I just free transform the image, all the horizontal lines will not be well "proportioned". It will take hours and even days to fix this image using photoshop. I just wanna take perfect picture out of the light box with minimum post processing. Thanks again!!!!

Edward Ng,

 

You should read "The Camera" by Ansel Adams. This will give you the foundations of perspective and the Scheimflug effect.

 

If you want something "perfect" off the light table, you will need a view camera. An Hasselblad with a PC Mutar attachment and a 40mm lens will give you a limited amount of "rising front" adjustment, but not as much as a view camera.

 

Most of the time, Photoshop is sufficient if you use it correctly. You keep the same proportions as a "rising front" if you make the perspective corrections symmetrical - stretch the top and squeeze the bottom equally, then crop the image. It helps to level the camera horizontally, or at least rotate the image in PS so that the centerline is vertical before applying perspective correction.

 

Vertical convergence can be reduced if you take the shot from an elevated position so you can keep the camera more level. It also helps to move further away and use a longer lens.

Ukrainian Hartblei perspective control lenses are quite good and relatively inexpensive (hundreds rather than thousands of $s). They're made in a P6 mount and can be easily adapted to many 645 SLRs (FWIW I use my 65 mm Hartblei PC lens on an Arax 60--a modified Kiev 60--modified in the sense that it actually WORKS right out of the box and has been reliable over three years of use).

 

If you're printing in a real (i.e. wet) darkroom, you can get similar perspective control by simply tilting the easle and stopping the enlarging lens well down. It's quite easy to do.