CPP Exam Question Discussion

[Betsy_Finn]

Since the Light Ratio vs. Lighting Ratio question prompted so much discussion, let's start a new thread just for discussion of exam questions! I'll start us off by grabbing another sample question from the sheet. For reference, here is the link to the PDF of Sample Test Questions.

Since we're not going in order anyways, I've chosen number 2!


A particular filter used with black and white film calls for an exposure factor of 8X. Applying this factor to the intial exposure reading of 1/8 second at f/32 will require a new exposure of

a. 1/8 second at f/22
b. 1/8 second at f/16
c. 1/4 second at f/22
d. 1/4 second at f/16

[David_A._Lottes]

I'll bite, I would say answer d. 1/4 @ f16. Why? 8X is four stops so slowing down to 1/4 gives you one stop, opening up to f16 gives you three more. 4 x 2 = 8.

[Mark_Levesque]

I'll go with C. 8X is 3 stops. (1 stop is 2X, 2 stops is 4X, 3 stops is 8X), right?

[Michael_Gan]

Both of you are half right. Mark is correct that 8x is 3 stops difference. But, C. is a 2 stop difference (f32 to f22 is one stop, 1/8 to 1/4 is 1 stop). D. is a combination of a 3 stop difference.


Michael

[Joseph_Froeschle]

Yes, It's 3 stops answer "D" is correct.

[David_A._Lottes]

Gotta love multiple choice! Even though my reasoning was wrong my answer was right. LOL! Thanks for straightening out my math Mark, I forgot to double each time I go up a stop, and thanks for clearing up the answer Michael. So 16-22-32 is three numbers but only two stops difference. Man I KNOW that, why did I think it was three! JEEEZ. This is great, I had no idea I was this rusty. Next question please!

[Betsy_Finn]

Alright good work guys, D is correct according to the sample sheet as well. Next question!

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

(only 3 options)
a. there will be a larger image size with the 35 mm
b. there will be a smaller image size with the 35 mm
c. there will be no difference in the image size

[Don_Chick]

Same thing that happens when you take your 300mm lens off your full frame DSLR and put it on a camera with an APS (smaller) sized sensor. The image is larger and you end up with a multiplication factor.

[Joseph_Froeschle]

A 300mm lens will project the same image size regardless of what camera it's mounted on. The correct answer is "C". The difference is the crop of the sensor or film size.

[Derek_Alvarez]

The image will be larger

standard MM for 35mm is 50mm and for medium it is 80mm