Using an 85mm PC

[hknauer]

I guess I must be getting older because I'm having some problems making peace

with an 85mm 2.8 PC lens that I purchased. The problems fall into 3 areas:

 

1. Exactly what should I be expecting with regards to depth of field gain when

tilting the lens. In the few situations that I've tried it, I don't seem to be

able to get both far and near in focus at the same time even though I shoot at

f32 or f45. If one assumes that with no tilt my plane of focus is parallel to

the sensor plane, will maximum tilt make the plane of focus perpendicular to the

sensor plane. Isn't a perpendicular plane of focus what I see when I see a field

of flowers razor sharp into the distance?

 

2. With regards to exposure. I have used cameras for 40 years and even teach

digital photography but this is the first truly manual lens that I have used. I

set the lens to 2.8 and balance the exposure in manual exposure. Then, as the

manual states, I rotate the lens "n" clicks to whatever f-stop I want to use,

stop down the lens by pushing that little button down, and balance the exposure

change by rotating shutter speed an equal number of clicks in the appropriate

direction. Rarely is the exposure close. I always seem to be about 3 stops

overexposed. Its gotten to the point where I just take a few shots and zero in

to the correct exposure based on what I see in the LCD and what the histogram

tells me.

 

3. I remember reading that you can use the shift mechanism to take a panorama.

I tried this with mixed results. I put everything in manual mode (I shoot raw

anyway) and then took three exposures with the lens shifted all the way to the

left, then the center, then the right. Since shifting left and right requires

exposure compensation, how should I accomplish that.

 

Any insight to all this would be greatly appreciated. If i don't hear from

anyone, you can contact me for a good price on an 85mm 2.8 PC.

[bruce_margolis]

Howard, I don't use a PC lens but maybe something from this article will help you......

 

http://www.uscoles.com/pclens.htm

[wharridge]

"Since shifting left and right requires exposure compensation, how should I accomplish that"

 

Shifting away from the central position should not require exposure compensation, my guess is that the exposure meter is deceiving you. Try metering in the central position, shifting and using the same (manual) exposure.

 

...Wayne

[alex_lofquist]

I've just started using this lens on my F5. It takes some getting used to. I first focus on something in the near field then tilt the lens to bring the far field into focus. (This is all done at maximum aperture.) You will probably have to recompose the subject at this point. If you have modified your lens to shift in the same direction as your tilt you can recompose by shifting. Redo the above to refine focus near and far. Then stop down to about f/11 or f/16 to gain the DOF that puts everything into acceptable focus. For macros I use centerweighted metering on a grey card before shifting, but check it again afterwards before exposure. If there is significant difference, I'll bracket the exposures. I use stopped-down metering, That is with the aperture "plunger" all the way in!

 

It's not easy but the rewards are worth the effort.

[ken_schroeder]

Howard, I believe at some future point, you will find the frustrations of the learning curve with this lens well worth the effort. The curve is made easier with a good tripod and an L bracket. (I discovered the joy of the L bracket only recently. It makes life a lot easier with vertical shooting. RRS makes some very nice brackets. Bogen/Manfrotto makes a very usable less expensive model which I bought for use with my 3047 head.)

 

The other piece of gear you may need is an eyepiece correction lens. The flip side of our forty years experience is older eyes.

 

About tilt....Imagine a piece of window glass parallel to the back of the camera. As we stop down the glass (plane of sharp focue) gets thicker. With the tilt feature, we are able to have the glass non parallel with the camera back. Imagine a field of flowers with a mountain in the background. By tilting the lens, we can lay the glass on the field and get both the near flowers and the distant mountain in focus. By stopping down, we can include taller flowers and bushes. If there is a tree branch , the classic "frame" in the top of the image, it will be far from the glass pane, and very out of focus. The only possible remedy is stopping down. This may or may not be enough to help, and the effect is counteracted by diffraction. My old f2 85mm lens is my favorite lens in any format. I use it more than the rest combined. However, it is mediocre when stopped below f16. I would forget f32 and f45.

 

What I would find more useful than the tilt is the shift. (I have been using 4x5 for 25 years.) The shift feature allows you to find the ideal camera position and then plumb the camera to keep things parallel. The classic use is tall buildings. The ability to shift the lens to keep things straight is useful in many areas.

 

The panorama effect would seem more suited to shorter lenses, in my opinion. It will certainly work, but the effects will be less pronounced with the longer lens.

 

Exposure should be the same as with any other lens. A sunny day which yields good results at 1/125 and f16 will be the same with the PC lens. I'm afraid I can't offer much help with automated exposure; I'm an old 20th century dinosaur who uses my eyes and occasionally a spot or incident meter.

 

The PC lens favors a more contemplative approach to photography. If you, like me, prefer a slower pace using a solid tripod, it is a very useful tool. I suggest you allow yourself some time to work with only that lens. Find a quiet area to work and bring only the PC lens, your camera, and the tripod. If your camera can use a grid screen, that would be useful. Leave all your other lenses, etc at home. Don't encumber yourself with extras such as filters. Spend a few days using only this lens. Spend enough time until you feel very comfortable with it. It may become your favorite lens.

[bjørn rørslett]

I use my 85 PC a lot and don't have the issues you mention. You must set the camera to "M" mode for exposure. Only when the lens is NOT shifted or tilted will the camera meter work as expected (this occurs with *all* tilt/shift lenses irrespective of their brand). Obtaining perfect panoramas with the 85PC is easy. Just secure a good exposure, then shift away. There is absolutely no need to change the exposure when the lens is moved away from the optical centre. This will work perfectly also when the lens is tilted before it shifts, by the way.

 

Extending DOF by tilting the lens is a little tricky unless you get experience in setting up the lens and camera for this operation. The common errors are (a) getting too close to the subject or too low to the foreground, (b) pointing the camera downwards in a too steep angle, and © not properly aligning the plane of focus with the plane of critical detail in the subject. If you don't set up correctly, there is no way you can stop down sufficiently to reclaim what's lost in DOF range initially. On the other hand, set up decently you can shoot landscapes with DOF extending from 1 m to infinity even with the lens nearly wide open. All it takes is just a wee bit of tilt.

[hknauer]

Thanks all. You have been helpful. I went out this morning and shot flowers in the bright sun to work it all out and I did.

 

I am not sure why you would want to modify the lens though. Since I am looking to use the shift for panoramas, wouldn't I want the t & S to operate 90 degrees from one another?

[bjørn rørslett]

Whether a modification is useful or not depends on how and what you shoot. I occasionally modify my own 85PC directly in the field, to parallell T/S or back again. It takes a suitable small screwdriver and 2 minutes of patience and care.