Focal length and 10D

There has been some confusion as to how it works and here's the answer: Take the focal length of the lens and multiply by 1.6 for the 10D. Note: you will loose 2 fstops for 2x TC!! For example: the F2.8 becomes a F5.6 at 2x TC length! Here are some to help you...
Lens size (mm) / Effective on 10D (mm) / 2xTC mm
14 / 22 / 44
15 / 24 / 48
20 / 32 / 64
35 / 56 / 102
40 / 64 / 128
50 / 80 / 160
70 / 112 / 224
80 / 128 / 256
100 / 160 / 320
200 / 320 / 640
300 / 480 / 960
1000 / 1600 / 3200

And so on. For 400mm, look at the 40 column and multiply but 10 to get 400 focal length. You can also get a download from CPS. Here's the site and you can even download it: http://www.cps.canon-europe.com …e.jsp?article.p​ageId=6510

Wow! Awesome find, Canuck!! Definitely worht the download and you can have this chart handy at all times. It's also flash embedded and has a handy little scrolling arrow for finding your lens/camera combo very easily.

Here's a jpeg of the chart:

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Sweet! Thanks, Jim! I wasn't sure how to imbed it.

No problem but it is still a must download. I have located right in my Photography folder and one click and it's up. Pretty cool.

I know where this will go if/when it materialises and so do you! This would be extremely handy.

Doesn't anybody do simple math in their head anymore?

---Bob Gross---

I can yes. I schooled before the advent of calculators. Nowadays you can't even get the kid at McDonalds to count out your change anymore. They just spew out a number and dump a pile of change in your hand and you have to count it out.

This chart is very handy though, you have to admit.

The early 4-function calculators were just coming to market when I was finishing engineering school. I couldn't afford one, so I went all the way through using a slide rule or a large book of log tables.

Of course, in the same early years we had to make the tough choice between 25-speed or 64-speed film. I think 64 cost more money.

Now we just spin the camera's rear wheel one way to get ISO 800 or something.

---Bob Gross---

Yes how the times have changed. The ASA25 was probably $1.29 and the ASA64 was probably as high as $1.89. I don't remember the prices, but that's probably pretty close considering the prices of film these days.

The thing about learning it the way we did (back in the infamous "old days") is that we actually learned more about how things actually operated, cameras, numbers, etc.

Now, everyone just learns what button (or wheel) to push and has no real idea what is actually happening that makes that button do what it does.

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