Wondered if someone in the know could explain something for me please

I'm looking at Canon stuff, so I'll use Canon models, but obviously the same could apply to Nikon etc...

99% sure I'm getting a 7D, this has an APS-C sensor with a 1.6x crop factor. Now, I know that essentially means that a 50mm lens becomes a ~80mm focal length.

Take a 50mm EF lens, and this will (as above) produce a ~80mm focal length, but will a 50mm EF-S (i.e. the series of lenses built specifically for APS-C sensors) produce a ~80mm focal length, or will it be a true 50mm lens (i.e. it's actually ~32mm lens).

Ta

It's focal length is 96mm on 35mm/full frame equivalent.

It is a 60mm EF-S lens designed for the smaller APS-C sensors (hence the lens is smaller & lighter) and to give users of these cameras as close an equivalent to the EF 100mm f2.8: probably their next selling fixed focal length lens.

http://m.dpreview.com/news/2005/2/17/canon_efs60mmmacro

Right, ok... so the EF-S lenses you still add the crop factor on, cheers

Yes.

The EF-S 60mm is a very good lens for the money. You get a short telephoto (ideal for portraits) as well as quite close focussing (for car detail shots) in a small, lightweight package for not a vast amount of money.

Yup, if you have a cropped sensor that will apply to all lenses, even "DX" lenses which won't work properly on a full frame or film camera

Crop factors cause totally unnecessary confusion. If you never had a 35mm camera (or full frame digital equivalent) then don't worry about crop factor. Just accept the perfomance of the lens to be what it is. No need to worry about what the lens would do on a full frame camera.

Look at it this way.

A car maker (let's call them Skoda!) makes a small car (called the P&S), a medium car (called the APS_C) and a large car (called the full-frame).

You can buy the small car with a 1.2, 1.4 or 1.6 engine

You can buy the medium car with a 1.2, 1.4, 1.6, or 1.8 engine

You can buy the large car with the 1.4, 1.6, 1.8 or 2.0 engine.

Lets take the 1.6 engine:

in the small car - 0-60 in 8 sec

In the medium - 0-60 in 9.5 sec

in the large - 0-60 in 10.5 sec

Looking from the other direction: to get 8 sec in the medium car you need the 1.8 engine, in the large car you need the 2.0 engine.

The engine size is what the engine size is - it doesn't change or take on a different meaning but it behaves differently depending on the size of the car.

Likewise the lens focal length is what lens focal length is and it behaves differently depending on the sensor size.

Because of the popularity of 35mm, the people switching from 35mm to digital needed to understand "what lens do I need on my APS-C digital to give the same effect as a 300mm lens on my old 35mm SLR". Just as you may say - what engine do I need in the large car I intend to buy to give the same performance as my 1.6 medium car.

But if it is your first car then why worry about that engine's performance in a car you never owned and never intend to buy?

Does that ramble make sense?!?!

The EF-S lenses take advantage of the smaller coverage needed on an APS-C sensor to make the lens smaller and lighter. The rear of the lens projects deeper into the camera body to project a smaller image. When you use an EF lens on an APS-C the edges of the projected image are wasted. You effectively take a "digital zoom" crop from the centre of the lens.

Canon's EF-S lenses will not mount on a full frame camera - I tried (very carefully to see what happens!!) to mount an EF-S 18-55 on my EOS film camera. It will not mount - the rubberised washer (wonder why that is there!!) around the projecting rear element fouls on the body throat. I didn't push very hard though! If it did mount then the mirror would hit the rear of the lens.

In contrast my Sigma 10-20 which is designed for APS-C does not have the extra projection and does mount on my EOS film body. Believe me I made some very careful measurements of the rear of the lens before the next bit! It takes photos on the film camera. Very heavy vignetting under 13-14mm but fantastic circular fisheye at 10mm!

Disclaimer - try this at your own peril! It worked on my EOS 50E - I cannot guarantee that it will not foul the mirror on full frame digital or other EOS film bodies!

Rather complicated car analogy there, but I agree! If you've never used a film SLR then it really matters not. It is more for those who converted from film to digital to get an idea of what focal length is equivalent to what they were used to. My dad gets a bit muddled by it all as he used film. Basically, if you had a 50mm on a full frame DSLR or on a film SLR it will appear less 'zoomed in' than it will on the normal DSLR because it is using a bigger sensor/negative. Imagine getting the print from the neg, then cutting off the edges, or cropping it. Thats basically what a cropped sensor does. also, cropped sensors aren't a set size, the Nikon ones are slightly bigger than the canon ones, then in compacts you're getting a tiny sensor!

My kit lens (18-135) is a DX (crop) lens. I have used it on my F80 (Nikon film body) and it works, but only when zoomed to a certain focal length. prior to that, I can take a photo but it will have a black vignette in the corners, because it can't fill the full negative. Can look ok though if you happen to want a vignette?! lol.

The digital cameras are more clever though, some will know if they have a cropped lens and will crop the sensor accordingly, so you cant take a picture at any focal length, but you have effectively turned your full frame camera into a cropped sensor.

sorry if I've repeated anything here, didn't have time to fully read the above!

Edited 30 July, 201213 yr by Loz

The EF-S lenses have a slightly different mount to the EF lenses.

If the collar on the camera only has a Red dot it will only take EF lenses.

If there is a white square, it takes EF-S lenses (and there will also be a red dot as well).

The rubber collar is for weather proofing / sealing the lens to the body. It won't be the reason why your lens won't fit.

By only utilising the centre of the lens / glass elements you are actually using the sweet spot of the lens and will get the minimum distortion, vignetting and maximum sharpness from the lens.

I wouldn't generally recommend trying to fit an EF-S lens on to a EF mount (or Nikon/Pentax/Sony/etc. equivalent).

The reason for stating 35mm eqivalence is to offer a 'standard' measurement by which focal length can be compared. A bit like energy ratings on houses/cars/tyres/boilers/etc.

I don't understand this Canon talk, and all Nikon fit are the same, whetehr DX or FX lens, but I agree about using a full frame lens on a cropped sensor! My 105 is a full frame lens and it takes the most beautiful, sharp, clear images. Noticably better than pretty much all my lenses. It is a macro lens too, so pretty sharp anyway. I wouldn't intentionally buy cropped lenses, not only because of the superior quality (and price lol) but for when I do upgrade to a full frame, I wont need hoardes of new, expensive glass!

The rubber collar is for weather proofing / sealing the lens to the body. It won't be the reason why your lens won't fit.

.

I don't think that can be true. The rubber ring is just around the protruding part of the rear element and is nowhere near the mount. Why would Canon weatherproof part of the lens that sits inside the body. Especially when the internals of the lens move into the lens when you zoom to leave a gap so big you can see the lens internals.

Here is an EF-S mount:

The rubber washer is the dark grey ring just inside the contacts. Compare to an EF mount

When I try to mount (VERY carefully!!) my 2 EF-S lenses on my EOS film body the first part to make contact with the EOS throat is the rubber ring. I think it is there to give an early warning to idiots like me, who ignore instructions, not to push any harder

If you compare the position of the rear elements on, the pictures above you will see that the rear element of the EF-S protrudes far more - beyond the lens contacts.

I don't understand this Canon talk, and all Nikon fit are the same, whetehr DX or FX lens,

You Nikon folk have it easy. You only have to worry whether you body has a focus motor or not. Us Canonites have different complications to consider.

Canon's EF-S series APS-C only lenses are different at the mount end (see above post). The bayonets are the same but EF lenses have less protrusion into the camera body than EF-S

Gets very complicated! I have 2 camera bodies - an EOS450D digital and an EOS50E 35mm

Of my 7 lenses

2 are Canon EF-S - so 450D use only and will physically not mount on the 50E

3 are Canon EF - use on either body

1 is a recent Sigma DC - designed and intended for digital APS-C only but mounts and works on my 50E with vignetting at the short end (same effect as Nikon DX/FX)

1 is an old Sigma that works fine on my 50E but because of electronics compatibility issues will only work at full aperture on my 450D else I get a lens error.

Not having had EF-S lenses, only have 'L' series now, for several years, I thought you were referring to the rubber seal between the metal collar body and the lens mount.

As I only have EF lenses, the bit you refer to have never bothered me...

Sorry.

Canon have tried to overcome the potential for people mounting the wrong lens on the wrong body with different mounts. Nikon users can use DX/FX lenses regardless and may not understand the consequences when they see their pictures.

Either user would be advised to invest in FX of EF lenses as these mount on either body format by either manufacturer and will be the best long term investment.

You can tell if you used a DX lens on a film body. With a digital it will just crop the sensor, so doesn't really matter

Nikon lol

Personally I don't understand why any of the manufacturers of DSLR's bothered with anything other than full frame sensors...

So much confusion caused for the 'entry level / enthusiasts' who these smaller sensor cameras are aimed at: it's not just focal length, but vignetting, loss of DoF, lens mounts, nomenclature, cross manufacturer compatibility or comparison, inconsistencies over crop factor (1.6 on Canon & 1.5 on Nikon I believe), etc., etc.

Throw in M4/3rds mounts, Nikon J and the new Canon EOS-M (I've almost been convinced to put one on order as it has an adapter for the EF lenses I already own) it's no wonder people no longer know ar*e from elbow in the world of photography.

At least back in 'the day' it was 35mm (film) for all but pro's and a 50mm lens was 50mm on everyone's camera and f4 produced the same result on everyone's camera.

And my lenses probably fitted your camera as Pentak K mounts were so common and there was so little reason to change.

Has camera technology really progressed so as to make it easier for us to get great pictures?

You tell me.....

P.S.: Sorry for the rant.

I shall repent and buy a Hassleblad!

Personally I don't understand why any of the manufacturers of DSLR's bothered with anything other than full frame sensors...

So much confusion caused for the 'entry level / enthusiasts' who these smaller sensor cameras are aimed at: it's not just focal length, but vignetting, loss of DoF, lens mounts, nomenclature, cross manufacturer compatibility or comparison, inconsistencies over crop factor (1.6 on Canon & 1.5 on Nikon I believe), etc., etc.

Throw in M4/3rds mounts, Nikon J and the new Canon EOS-M (I've almost been convinced to put one on order as it has an adapter for the EF lenses I already own) it's no wonder people no longer know ar*e from elbow in the world of photography.

At least back in 'the day' it was 35mm (film) for all but pro's and a 50mm lens was 50mm on everyone's camera and f4 produced the same result on everyone's camera.

And my lenses probably fitted your camera as Pentak K mounts were so common and there was so little reason to change.

Has camera technology really progressed so as to make it easier for us to get great pictures?

You tell me.....

What would they sell you if they didn't keep changing things?

Personally I don't understand why any of the manufacturers of DSLR's bothered with anything other than full frame sensors...

Are you serious? One word - PRICE

As for knowing ar*e from elbow - that's a bit generalised, narrow minded and insulting tbh. It's really not difficult to grasp.

My comment was generalised and not aimed at anyone in particular. If I offended any individual person then I apologise.

Loz - you understand it and I understand it, but my comments are based upon years of teaching a beginners course in photography and seeing people coming through having invested well over £1k in camera & lens without knowing why they bought that particular system. Or people spending £450 on a combo then realising that it was wrong for their needs and then spending more on the equipment they really should have bought / been sold.

I am still shooting professionally on Canon 5D Mk1's (7 years old) and see no real reason to change. I personally spend the money on learning from the best which will, I hope, improve the quality of my pictures more than a new camera will.

As for ignoring the 35mm equivalent, I disagree. Understanding that anything less than 50mm (on 35mm/FF) focal length gives a wider field of view than the human field of vision or vice versa can aid our understanding of why the lens performs as it does and also how it effects the finished result.

Surely no one would disagree that shooting a 'formal' portrait on a wide angle lens is a good idea?

At least back in 'the day' it was 35mm (film) for all but pro's and a 50mm lens was 50mm on everyone's camera and f4 produced the same result on everyone's camera.

P.S.: Sorry for the rant.

I shall repent and buy a Hassleblad!

Was the irony intentional :rofl:

Because of the 6cm square negative in a Hasselblad then an 85 mm lens is the 35mm film equivalent of a 50mm lens - ie compared to a medium format film camera, 35mm film has a 1.6 crop factor

Personally I don't understand why any of the manufacturers of DSLR's bothered with anything other than full frame sensors...

So much confusion caused for the 'entry level / enthusiasts' who these smaller sensor cameras are aimed at: it's not just focal length, but vignetting, loss of DoF, lens mounts, nomenclature, cross manufacturer compatibility or comparison, inconsistencies over crop factor (1.6 on Canon & 1.5 on Nikon I believe), etc., etc.

Throw in M4/3rds mounts, Nikon J and the new Canon EOS-M (I've almost been convinced to put one on order as it has an adapter for the EF lenses I already own) it's no wonder people no longer know ar*e from elbow in the world of photography.

At least back in 'the day' it was 35mm (film) for all but pro's and a 50mm lens was 50mm on everyone's camera and f4 produced the same result on everyone's camera.

And my lenses probably fitted your camera as Pentak K mounts were so common and there was so little reason to change.

Has camera technology really progressed so as to make it easier for us to get great pictures?

You tell me.....

Some sweeping generalisations is that rant

The confusion only arises because for some reason folk insist on relating lens behaviour to a 35mm negative size. If you only have one camera then all you need to know is what lens do I use and where do I need to be to get the best framing for my photo. Don't forget that some P&S have minute sensors with crop factors of 5. Do you think that owners of these have sleepless nights worrying about what is the 35mm equivalent focal length of their 6 to 60mm zoom lens. It is a case of a little knowledge being dangerous.

I currently use 3 cameras - a Canon EOS 50E (35mm film), an EOS 450D (digital) and a Canon Powershot A1100 IS (digital point and shoot). Haven't a clue what the crop factor is for the P&S - it has a 6-24mm lens and it fits in my pocket! When I am deciding which lens to use on the SLRs I never even think about focal length equivalents.

Ermmm I never had a Pentax K mount in 50 years of photography - an uncle gave me my 1st camera when I was 7 or 8 - a Kodak bellows Anistagmat with an 80mm f/6 lens and shutter speeds 1/15 to 1/200 plus B and T . After another couple of cast-off 120 film bellows Kodaks I had a few 35mm compacts - NB there were no zoom lenses - all had fixed lenses with single focal length - you zoomed with your feet, in addition you focused by estimating the distance and used the sunny 16 rule for exposure. . My first DSLRs were Practikas with Pentax 42mm screw prime lenses, upgraded to Canon FD mount with an AE-1 in 1977 and had Canon SLRs ever since.

When I look at pictures of that old Kodak bellows camera with no metering, waist level prism viewfinder (plus pop-up double metal frame eye level), guess the focus - like this

and compare it to what I have now

Then I think technology has progressed a VERY long way :rofl: :rofl:

If people are happy to go out and spent a grand without a clue why they did it then that's their look out! A small amount of research before hand is all that's needed. If crop sensors weren't made then digital photography would be out of reach for most ordinary people. Especially when it first came out! Which is why Nikon are meant to be releasing the D600, a "budget" full frame camera.

I think eccleshill is getting the point - all you need to know is how it performs on YOUR camera in order for a good enough understanding to be shooting pictures. Just because you don't know the 35mm equivalent does not mean you would shoot a portrait with a wide angle!

Eccleshill - not long ago I bought a Yashica 124G MAT, I think I'm going in the wrong direction lol

Was the irony intentional

Yes!

Then I think technology has progressed a VERY long way

But have the technological improvements actually improved our abilities to create better pictures?

Nikon/Canon?

Film/digital?

Prime/zoom?

P&S/medium format?

Surely photography is not about the camera but the photographer?

But have the technological improvements actually improved our abilities to create better pictures?

Surely photography is not about the camera but the photographer?

Absolutley agree with that last statement 100%

I would say that a photograph is 50% photographer, 25% lighting, 15% lens, 10% camera body. There used to be a really good programme on TV with James(?) Ong. He would get 3 pro photographers with at least 1 a declared anti-digital. He would give one a top range DSLR, one a mid range digital point and shoot with some manual control, the 3rd got a bottom range full auto only P&S or, sometimes, a mobile phone. They were sent out on a project and in every case all 3 would come back with results to die for!

Technology brings its own problems but I would say that the biggest technological advance is the ability to take lots of photos at zero additional cost. I don't mean use the camera as a machine gun with every million shots producing one masterpiece, I mean the ability to take a shot, look at it, work out how to improve it, take it again. Also the ability to record in the EXIF how the photo was taken so you can go back and learn from the final result. This alone means you can get the experience in one afternoon with digital that would take a year with 35mm film.

That is one way that technology has advanced our ability to improve our skills and thereby create better pictures.

Creation of a good picture doesn't stop when you press the shutter. Digital allows us to have a dark room on our PC. I don't mean taking crap photos and creating something out of them with photoshop. I mean shooting RAW and processing your own jpg. I like to think of RAW files as my negatives. Process the RAW file as you would create a print on the enlarger with a few extra abilities - adjust overall brightness/contrast/colour balance, raise/lower shadows/highlights, clone out intrusions, crop, adjust lens distortions....

That is another way technology helps us to create better pictures.

Is this a case of Life of Brian - what have the Romans ever done for us...

But have the technological improvements actually improved our abilities to create better pictures?

I'd actually goes as far as to say that it has reduced our abilities to create better pictures.

For the simple reason that with any form of digital camera the photgrapher (amateur, not professional) can take any amount of pictures of the choosen subjet in the hope that 1 or 2 come out ok, the rest are consigned to the electronic trash can. Therefore the thought, effort and consideration that a film photographer would put into composing a photo, knowing that every poor image was still costing him/her money, is gone.

Combine this with the digital image manipulation software which can be bought for low cost or is even free then there is even less reason to put in the effort up front.

Don't get me wrong, I think digital is a great format and the ease with which it can help poor/inexperienced photographers take technically compentent shots is impressive, but that doesn't guarantee your friends and family won't get equally bored with looking at your holiday snaps. Actually they'll get even more bored as now there will be 100 or more whereas before there might be 36 at a push