Focal Lenght Question

OnLooker

Hi,

You might be able to explain this better for a friend of mine. I am brutal at explaining stuff.

He recently got a Canon 400d & has a question regarding the focal lenght when a len's is put on it.

What focal lenght would a 70-200mm & 70-300mm give and what metre distance is this is lay man's terms.

brackerknacker

I was just going to ask the same question. I also recently purchased the 400d. I like to shoot sports and I am looking into what type of len's in best for my needs.

Fajitas!

Basically, you multiply whatever focal lenghts by 1.6.

magicbastarder

OnLooker wrote: »

What focal lenght would a 70-200mm & 70-300mm give and what metre distance is this is lay man's terms.

to be trite, the focal length they'd give is 70-200mm, and 70-300mm.
focal length is focal length, but i assume you're talking about 35mm equivalent, which is the effect this focal length has on a DSLR in comparison to a 35mm camera?

brackerknacker

So if had a 200mm * 1.6 = 320mm , what distance (metre wise reach) would this give me in the field?

Oriel

Fajitas!, I think it's more retarded than that.
They're asking now many meters does a 300mm "stretch", when you look through the viewfinder.
brackerknacker, the "300mm" means the light is reflected 30cm from between the first glass on the lens to the camera censor.
It's just to try one out.

Thirdfox

I think generally photographers talk about degrees when describing how much "zoom" a lens gives:

e.g. a 300mm lens gives roughly a 7.9 degree view
7mm gives 200 degrees view(?)

our normal vision incorporates around 150 degrees (with a very small circle in focus).

To get good photos of Jupiter you would need a lens that gives 0.001 degree view

brackerknacker

Thirdfox wrote: »

I think generally photographers talk about degrees when describing how much "zoom" a lens gives:

e.g. a 300mm lens gives roughly a 7.9 degree view
7mm gives 200 degrees view(?)

our normal vision incorporates around 150 degrees (with a very small circle in focus).

To get good photos of Jupiter you would need a lens that gives 0.001 degree view

What does that mean in lay man's terms?

sineadw

Actually if someone could settle a slightly off-topic argument.. The human eye - what's the film lens equivalent? I remember eons ago reading it was about 50mm but my 3d max instructor reckons its about 35mm (its for a room walkthrough so its not entirely academic :rolleyes: )

OP - do you mean what zoom you'll get?

Thirdfox

45mm I thought was the human eye equivalent (so 50mm is the "normal" prime).

Valentia

brackerknacker wrote: »

what distance (metre wise reach) would this give me in the field?

How deep is a hole?

What do you mean? Do you mean how far away does a person need to be to fill the frame with a 200mm? Do you mean how far away does a Euro coin need to be to fill the frame? The question on its own has no answer.

Borderfox

Hope this helps. The first picture is a 50mm and the second is at 500mm I would say the 500mm was about 150ft away

50mm


500mm

440Hz

There was a really great demo online, a flash demo, on the tamron site I think which let you let you virtually zoom in and out to see this in action, cant find the link now, im sure I have it at home though.

digitalage

http://www.tamron.com/lenses/learning_center/tools/focal-length-comparison.php

440Hz

digitalage wrote: »

http://www.tamron.com/lenses/learning_center/tools/focal-length-comparison.php

Cheers, I knew I posted it before, but didnt have time to search, saves me a job now.

Oriel

sineadw wrote: »

The human eye - what's the film lens equivalent?

It's roughly 70mm for me, on a Nikon D80.