The 5% Solution

Started Aug 5, 2014 | Discussions thread
OP Stephen Barrett Contributing Member • Posts: 683
Re: The 5% Solution

Don_Campbell wrote:

I confess to not reading your original post thoroughly or carefully. I am pretty sure I missed the point of your exercise and also confess that after going back over it I'm not a lot clearer as to the point.

Hello Don,
You are right. I haven't been very clear about the point of it all. Originally, the intention was to estimate how large a subject was in shots taken with a closeup lens. But then I got interested in the optics and found that my calculated image sizes appeared to be too large to fit on on the sensor. So the point is now: What is going on? Is the sensor larger than specified or are focal lengths smaller than specified? According to Bob Atkins, SLR telephoto lenses have actual focal lengths that are, on average, about 5% smaller than specified values. Why would manufacturers do that?

So there is no very practical point to this thread - just curiosity about what is going on inside the camera.

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