Calculating Zoom in X

sbtm · 27-07-2006, 10:02

Hi folks,

I am fairly new to the advanced digital cameras and still haven't gotten the hang of all the mm's for the lenses...

Is there a way to know the zoom in terms of how many times (x) from the mms on the lenses? Like if it is a 10x or 20x?

Thanks

***Dave*** · 27-07-2006, 10:22

Hi sbtm

The simplest method is to divide the longest mm of the zoom, by the widest mm of the zoom. For example the Nikon 18-200mm is 200/18 = 11.1 x zoom range.

***Dave*** · 27-07-2006, 10:32

You might find this diagram helps show the difference of mm at the wider end of the lens range. This shows a comparison of what you would capture with each mm range. Note most kit lenses start at 18mm, which is considered wide angle, so anything lower is really only applicable if you wanted to go ultra wide with shots. Hope that helps & don't hesitate to ask anymore questions.

sbtm · 27-07-2006, 11:23

wow you guys are good :-) Thanks

I guess talking in terms of x zoom isn't professional isn't it? I'll try to get used to the mm's

**stepheno** · 27-07-2006, 11:27

Nice house you got there Dave

***Steve*** · 27-07-2006, 11:40

Quote:

Originally Posted by sbtm

wow you guys are good :-) Thanks

I guess talking in terms of x zoom isn't professional isn't it? I'll try to get used to the mm's

Nope you can talk of zoom in terms of x as long as its clear, there is nothing wrong with that

Most people tend to talk in terms of mm though when reffering to pictures and lenses as its easy to compare to what they are using without having to calculate the zoom factor for their own equipment...I think we are just lazy

orangepeel · 27-07-2006, 12:25

Quote:

Originally Posted by Steve

its easy to compare to what they are using without having to calculate the zoom factor for their own equipment...I think we are just lazy

which imo is only relevant if everyone talks in 35mm terms (which I doubt most do)

Your, and my, 100mm lens bears no relation to an olympus 100mm lens.

I think yours would be 160mm in 35mm terms, mine would be 150mm and the oly would be 200mm

just to confuse things a little more

sbtm · 27-07-2006, 13:21

Quote:

Originally Posted by orangepeel

I think yours would be 160mm in 35mm terms, mine would be 150mm and the oly would be 200mm

just to confuse things a little more

Hmmm... no wonder I don't get the hang of all the mm's

***Steve*** · 27-07-2006, 13:47

Quote:

Originally Posted by orangepeel

which imo is only relevant if everyone talks in 35mm terms (which I doubt most do)

Your, and my, 100mm lens bears no relation to an olympus 100mm lens.

I think yours would be 160mm in 35mm terms, mine would be 150mm and the oly would be 200mm

just to confuse things a little more

I am sorry but I have to disagree.

A 100mm lens is still a 100mm lens no matter what camera body you put it on. The problem is one of crop factors which many people mix up with true zoom lengths.

orangepeel · 27-07-2006, 14:18

I know the "looks zoomed" explanation is simplistic and technically wrong, but I've not yet seen an understandable explanation of the crop factor and why the same mm looks different on some bodies.

I get that the smaller sensor is cropping the view, but when you look at the same image on 6mp cams with the same mm on different sensor sizes the smaller sensor size looks as though it's zoomed in.

I guess I just don't get this whole thing and why it's wrong to say it "looks zoomed"

I've still not seen an explanation that is readily understandable in the same way that "it looks zoomed" explains it.
I hearby challenge you

if u can make this idiot understand then anyone can get it

***Steve*** · 27-07-2006, 14:36

Quote:

Originally Posted by orangepeel

I hearby challenge you

if u can make this idiot understand then anyone can get it

Why type it all out yourself when someone else has already gone to the trouble

Crop factor/zoom lens explination

Hopefully that will help

orangepeel · 27-07-2006, 15:23

Bookmarked! However it still doesn't explain why "zoomed in more" is wrong.

Even the examples still look as tho it's magnified.

Quote:

OK, firstly, when you put a 300mm lens on a D60 you do NOT get a 480mm lens – it is still a 300mm lens.

Fine, but to get the same fov on a full frame cam you will need a 480mm lens so why not just call it 480mm on the D60?

An example of this would be this image here for the derelict assignment: -
http://www.pixalo.com/gallery/showph...to/965/cat/553

If Foxesbrew was to quote 7.4mm it'd confuse the hell out of all of us... so better to call it in 35mm terms no?

In essence it seems to me to be a pedantic argument - with the exception of the DOF issue which I hadn't considered before