10 D - The 1.6 factor and the Exposure compensation.

[photomd]

Dear friends -

 

I have finally received my 10D yesterday and I am so excited about

it!

 

I want to share the following thoughts with you, hopefully, to open

a useful discussion -

 

1- Regarding the 1.6 "telephoto" effect. I am afraid that this

statement can be misleading. "Telephoto effect" as a term gives me

the impression of CROPPING+MAGNIFICATION. But my simple, primitive

tests confirm the cropping but not the MAGNIFICATION. I pointed my

Canon 75-300 on an object big enough to exactly fit between the

upper and lower AF points that appears in the viewfinder. I noticed

that the object fits between the two points at 75mm (on 10d) and

around 85mm (on Rebel 2000) not 120mm (75X1.6) as I expected. I

initially concluded that even though the image is further cropped

the objects are not bigger. please try it and let me know.

 

2- I noticed that the Exposure compensation (EC) mechanism in 10D is

the opposite to its counterpart in Rebel 2000. I learned that the

first rule in exposure (in analog cameras) that the meter "tries" to

make the object "look" midtone. So if I shoot a bright object I have

to compensated by moving the EC indicator to + and if I am shooting

a dark object I have to move it to -. I noticed that the

compensation on 10D is rather the opposite. Excuse me, if this fact

is taken for granted. After all, I am still a novice (D)photographer.

 

3- Last but not least, I have to thank photo.net for the good advice

about the 10D and Ritzcamera. The 10D: $1500. Ritzcamera courtious

service: PRICELESS.

 

Thank you and I hope to receive some comments.

 

Dr. Nabil Majid

[steve_dunn2]

<p>1. It's cropping. If you use the same actual (as opposed to effective) focal length to take the picture with each camera, the 10D image is a cropped version of the Rebel image.</p>

 

<p>Now, if you take the 10D image and the Rebel image and produce prints of both, with each print being the same size (e.g. 8x10"), you'll notice that the 10D image is magnified - the subject appears larger. But that's not because the 10D did anything to magnify the image; it's because you magnified it more while printing. In doing so, any lack of sharpness inherent in the lens will become more apparent, just as it would if you were to take a picture using the Rebel and make an 8x10" print of the whole frame, followed by an 8x10" print of just the middle of the frame.</p>

[gerard]

Nabil,<br>

This article is right for you: <A Href="http://www.photo.net/canon/10D/new_user.html">New User Guide to 10D</A>

<br>

-regards,

[Ken Katz]

It is cropping, not magnification. Regardless, with the same lens and shot from the same position, a 4" x 6" full frame print of an object photographed by your 10D will be about 60% larger than a similar print from your Rebel.

 

A cannot agree with you observation of exposure compensation. To me, it works very much like shooting slide film. If I take an exposure reading off of snow with a D60, it still needs + 1.5 to +2.0 stops compensation to keep the snow from graying out.

[bobatkins]

(2) is wrong. With ALL cameras, if you need EC you use +EC for light objects and -EC for dark objects. Rebel, 1v or 10D, it makes no difference.

[severi_salminen]

Nabil, your test is flawed. You can't make any conclusion based on what you see in viewfinder (unless you know the viewfinder specifications precisely). You don't know if the focus marks are spaced identically or in the same relationship in both cameras, the viewfinder coverage might be also different etc.

 

If you take a picture of a subject that covers the whole frame (the final picture, not viewfinder) with 10D at 75mm, then the subject would fill the frame with Rebel 2000 at 120mm.

 

And "magnification" is a totally irrelevant term here. _If_ 10D has a 36x24 sensor and some kind of magnifying lens in it, the results would still be the same as now with cropping.

[photomd]

Thank you all for you quick and informative responses.

[photomd]

Regarding all the responses about the exposure part of my comment... I went outside during the last hour of a sunny day. I pointed 10D to trees where the tonality are midtone to -1. The picture in the viewfinder was +1 to +1.5 overexposed. Should I redo it using the rebel (and I did it before) it appears midtone (provided in both cases the shot was with EC set at 0) I will repeat the test tomorrow using 18% gray card and I will let you know.

[Ken Katz]

If you meter and shoot an 18% graycard, the peak on the resulting histogram (much better than viewing the photo on the LCD), should be somewhere in the middle (maybe a 12% gray card will be in the middle). If you add +1 EC, the peak should shift to the right. If you subtract -1 EC, the peak should shift to the left.

[whayne_padden]

Nabil if you pointed the camera at a tree you thought was mid toned and shot at the suggested exposure and the results came back overexposed to you then clearly the tree was not midtoned but at least -1 EV darker than mid toned. You have to compensate for this by applying -1 EV correction to the cameras reading. The camera is calibrated for a mid tone and to make a dark object appear mid tone it added more light hence over exposed.

 

If you beleive that the 10D works opposite to other cameras you are mistaken or have a seriously flawed camera.

[johnlund]

Nabil, make sure you compare apples to apples. Meter in controlled lighting, and make sure each camera's meter sees exactly the same scene, no more, no less.