Frame size and lenses

[pihjin]

October 30, 2008 at 12:25 am

I know I should know this by now but it all seems so confusing…

Could someone please explain to me the difference in ‘full frame’ cameras and ‘not full frame (?)’ cameras and then what the lenses mean in relation to this too.

I use a Canon 400D but in about a year I know I will want to buy something like the 5D mkII.
If I buy lenses in the meantime for the 400D will they then be un-usable on the 5D mkII?

I really need a ‘for dummies’ explaination on this one as I don’t really know what the letters beside lenses mean! I know it’s some sercet code that will unlock all these answers for me!

Thanks everyone…

[MartinOC]

October 30, 2008 at 1:26 am

Here is an explantion in my own word. Now there is probably someone out there who can explain it better, but I’ll have a go…

What it means is that the sensor at the back of the camera is smaller than that of traditional “35mm” film.
So the image caught by the sensor is a bit less than that of a full frame (like “35mm” film).
It misses out a bit of the top, bottom and sides, relative to what a full frame sensor or 35mm film captures.

Lenses are described, by convention, using their focal lengths. But normally what is important to people is how much field-of-view (zoom) they have.
Eg If you are interested in a small part of the scene in front of you then you use a telephoto zens (a butterfly on a leaf),
or a wide angle angle for all of the scene they see (the whole pitch at Croke park).

For 35mm film (or full frame sensor) there is a natural field of view associated with each type (focal length) of lens.
But now we have this new small sensor size but we use the same lenses. For example if you stick a 135mm lens on on your 400D
we get a field of view that is smaller than would be on the 5D.
The image hitting the back of the camera is the same but the part we record is cropped, relative to the bigger sensor or film.

The field of view on the 400D with the 135mm lens is similar what you get with a 200mm lens on a fullframe.
People naturally like to think in term of field-of-view, even though lenses are described by focal length, so a “focal length equivalent field-of-view”
multiplier is used (i.e. 1.6 for the canon 400D).

A 400D with a 135 lens records a field-of-view like a full frame sensor with a 200mm lens (135 * 1.6 = 216). The multiplier is handy but remember
that the lens focal length is a property of the lens and doesn’t change with what camera its on.
The multiplier is a reference for people to compare the field-of-view between crop sensors and 35mm film or full frame cameras.

Hope that doesn’t confuse you more.

Most Canon lenses will work on both types of cameras (the usual EF lenses), but Canon has brough out a new line of lens which only work on crop sensor
cameras (eg 400D, 50D), these are marked as “EF-S”. They will not work on full-frame cameras because the are built smaller to take advantage of
the smaller mirror system on the crop camera bodies and will damage the bigger mirrors on the full frame camera.
I have the 10-22mm EF-S for my 400D.

Of the rest of the code of lens markings the aperature is next…..
Perhaps a course would be good for you, there are a few by the site sponsers.
Good luck,

Martin

[Ballyman]

October 30, 2008 at 8:18 am

MartinOC wrote:

Most Canon lenses will work on both types of cameras (the usual EF lenses), but Canon has brough out a new line of lens which only work on crop sensor
cameras (eg 400D, 50D), these are marked as “EF-S”. They will not work on full-frame cameras because the are built smaller to take advantage of
the smaller mirror system on the crop camera bodies and will damage the bigger mirrors on the full frame camera.
I have the 10-22mm EF-S for my 400D.

This is the most important bit. EF lenses will work on all Canon DSLR Cameras whereas EF-S Lenses will only work on cropped body cameras (400D, 40D etc.)

Therefore if you ever think you might upgrade to a 5D then only buy EF lenses.

I believe Sigma lenses are compatible with both full and cropped frame but I’m not 100% on that.

[paul]

October 30, 2008 at 12:15 pm

Canon produce 3 sensor sizes –

Full frams – such as 1Ds and 5D series
1.3 crop – 1D series (APS-H sensor)
1.6 crop – 1000D, 400D/450D, 40D/50D series (APS-C sensor)

Then you have the two types of lens – EF and EF-S

The EF-S will ONLY work on the 1.6 crop bodies. (white square block on the lens at the connection point)
EF will work on all Canon bodies. (red dot on the lens at the connection point)

So, in relative terms – say you use a 100mm lens.

On a 1.6 crop your lens will give you the effective image of a 160mm lens
On a 1.3 crop your lens will give you the effective image of a 130mm lens
And on a full frame, it will give you the actual 100mm range.

Is that clear and simple enough?

[pihjin]

October 30, 2008 at 11:32 pm

Thank you everyone…
All the answers have made it very clear to me..
I think it was the EF-S that was mainly confusing me and the red dot/white square will definatly help me keep it clear in my mind!

I don’t feel so silly now.
I think is was a case of how, you know when you meet someone new and are introduced but you don’t catch their name? And then the longer it goes on, you chatting to them and getting to know them, the more embarrassing it is to ask the simple basic question… that’s kind of what this was like!

Thanks again!