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Deleted
01-26-2006, 01:29 AM
Ok, someone smarter than me help me. On the PPA website, in the "Certification" area/link, you can download some sample test questions that are supposed to be similar to what is on the actual test.

So, question #4 states:

If focusing on the same subject at the same distance, what will happen to the image size if a 300mm (12 inch) telephoto lens is used on a 35mm camera compared to a 300mm (12 inch) lens used on a medium-format camera?

a. There will be a larger image size with the 35mm
b. There will be a smaller image size with the 35mm
c. There will be no difference in the image size

According to the test, the correct answer is "c", no difference ... which I think is incorrect. I believe the image is actually smaller on the medium format due to the film size being larger, all other things being equal ... is that not the case?

Help!

KirkDarling
01-26-2006, 01:51 AM
The correct answer is "no difference."

Focal length is focal length is always focal length. That's why a 50mm lens looks like a normal lens on a 24x36mm format but looks like a telephoto on an APS-C format. The image projected on the sensor is exactly the same physical size in either case, but format is smaller.

Let's say you have a 6x7 medium format camera with a 6x7 back on it. I put it on a tripod and mount a 127 lens, which is just a tad bit of a telephoto. I frame a head-and-shoulders shot.

Now I remove the 6x7 back and put on a 645 back. I've done nothing else but reduce the size of the film gate--it's the exact same lens projecting the exact same image. But where the framing was a head-and-shoulders shot with the big 6x7 film gate, the itty-bitty 645 film gate doesn't cover as much of that projected area--it's only big enough to capture the head of the subject.

Another example in the opposite direction. Set up a slide projector, projecting a head-and-shoulders shot onto a 3x3 foot screen. Now, change nothing about the projector, but replace the 3x3 foot screen with a 1x1 foot screen. The projected image is exactly the same size, but the itty-bitty screen only contains the face of the subject.

Deleted
01-26-2006, 02:03 AM
Ah, makes perfect sense ... I like the slide projector example. Excellent, really solidified it for me :-)

KirkDarling
01-26-2006, 07:41 PM
Ah, makes perfect sense ... I like the slide projector example. Excellent, really solidified it for me :-)

There is a question on that example test I'd take issue with, though. One question asks "which of the following styles of lighting would be best to use" to photograph some diamond jewelry.

The correct test choice is "Non-Directional."

IMO, however, that results in a lackluster picture of a subject that should, literally, be full of luster. I'd use some carefully directed snooted light from any direction rather than "non-directional," judging the proper angle through the lens to get the most picturesque highlights.

In the case of this test, however, that would make every other choice a correct answer--meaning that the single incorrect choice must be the answer to choose (psych!).

I also noticed that someone could select the last choice across the board and score 60%, which isn't passing but is the kind of test-build glitch I learned in my test-building studies to be wary of.

Leon_Adelstone
01-27-2006, 04:15 PM
I don't know what optional answer were available, but here's the answer.

Dija ever notice, in a restaurant with chandeliers, how your wife's diamond sparkled "fire", more than in other atmosphere's? That's the answer.

Dija ever notice the type of lighting in Jewelry stores? That's the answer.

Multiple "point source" lights. I've successfully used strings of Christmas Tree Lights.

KirkDarling
01-27-2006, 04:41 PM
The other choices were toplight, sidelight, frontlight. All directional.

The christmas tree light idea sounds good, as is the concept of multiple points. I think we probably agree that "non-directional" is certainly safe, but not very exciting for a diamond.