Newbie 400D & Lens Questions

[peterguk]

OK i've just treated myself to a new DSLR kit.

Boxed set of Canon 400D, battery grip, with EF-S 18-55MM and EF 50-200MM lenses.

£395 all in. Probably not the cheapest deal but seems good to me.

Can someone explain the difference between EF and EF-S, and also i see some lenses advertised as having US???

finally, i found this 400D related post elsewhere in this forum:

not every one is going to go full frame or if they do they can sell their digital only lenses. not buying efs or digital only lenses means you don't have some of the best lenses or the FL required for a 35mm equiv 16mm. if I ever upgrade to a 1d series (1.3x) I'll just sell my digital lenses no biggy

Explain please?

[tank slapper]

peterguk said:

OK i've just treated myself to a new DSLR kit.

Boxed set of Canon 400D, battery grip, with EF-S 18-55MM and EF 50-200MM lenses.

£395 all in. Probably not the cheapest deal but seems good to me.

Can someone explain the difference between EF and EF-S, and also i see some lenses advertised as having US???

finally, i found this 400D related post elsewhere in this forum:

not every one is going to go full frame or if they do they can sell their digital only lenses. not buying efs or digital only lenses means you don't have some of the best lenses or the FL required for a 35mm equiv 16mm. if I ever upgrade to a 1d series (1.3x) I'll just sell my digital lenses no biggy

Explain please?

Most digital SLRs have a sensor that is smaller than the size of a 35mm negative. The 400D is one of these. Other cameras like the 5D have a sensor that is the same size as a 35mm negative, and these are referred to as full frame cameras.

The image projected onto the sensor by a normal EF lens is bigger than necessary for a cropped frame sensor like that in the 400D. This means that it effectively only uses the central part of the lens, and has the effect of multiplying the focal length. eg A 100mm lens used on a 400D will produce the same image as a 160mm lens on a full frame sensor. EF-S lenses are designed with this in mind and tend to be physically smaller and lighter. This does mean that they can't be used on a full frame camera, so if you wanted to upgrade to a 5D in the future you couldn't use the EF-S lens on it.

I assume US was a typo for IS, in which case it stands for Image Stabilised. These lenses have a mechanism that detects vibration as you hold the camera and moves a lens element to compensate for it, making it easier to get sharp images. It is very effective and makes shooting in low light or with slower shutter speeds a lot easier.

[peterguk]

Thanks for concise reply Tank Slapper :-)

So, if i understand correctly, an EF-S lens will behave the same as it's focal length, whereas a EF won't.

I think the US was possibly ultra sonic... Unless i've got it wrong and your explanation is correct!

[tank slapper]

peterguk said:

Thanks for concise reply Tank Slapper :-)

So, if i understand correctly, an EF-S lens will behave the same as it's focal length, whereas a EF won't.

Not quite - any lens you put on a crop frame camera will have its effective focal length increased whether it is EF or EF-S. A 50mm EF lens will give you the same picture as a 50mm EF-S lens. The image below represents a full size 35mm frame.



The green line in the middle represents the size of 400D sensor, which gives a crop factor of 1.6. An EF lens has to project an image big enough to cover the whole picture, whereas the EF-S projects an image just big enough to cover the green rectangle. All that happens when you put an EF lens on your camera is that the area outside the green line is not used. If you could mount an EF-S lens on a full frame camera, you would get an image with the corners missing.

peterguk said:

I think the US was possibly ultra sonic... Unless i've got it wrong and your explanation is correct!

USM is on some lenses, and it refers to the type of motor that is used to drive the focusing mechanism.

[RobDickinson]

For the US bit you have 3 basic focusing mmotor systems on canon.

Non USM - like the kit, slow.

micro USM - step up from above, little bit quicker.

Ring or 'full time' USM - the real deal - fast and you can manualy adjust AF at any point.

Micro USM is cheating with the name a bit by canon, dont pay extra for it.

[miniman]

Quinny said:

EF 70-200 f2.8 "L" "USM" "IS" it costs over £1000

And it's bloody marvellous and worth every penny!

[mogul]

Quinny said:

And finaly "L" on any lens means that it is one of Cannons highly desirable proffesional lenses that cost lots

So when you see a lens that features all of these letters ie

EF 70-200 f2.8 "L" "USM" "IS" it costs over £1000

Bloody good lens though

[flat-planedCrank]

Quinny said:

All canon digital cameras except the 5D have a crop factor.

Quinny said:

An EF or EF-S lens can be used on any of the above cameras except the 5D which can only accept EF only

Just for completeness (and to be a picky devil ) would just add the 1Ds series to that list of Full Frame cameras that wont take EF-S lenses.

The 1d series (APS-H sensor) will also not take EF-S lenses.


(all these options are definitely at the pricer end of the scale )


Cheers.

[RobDickinson]

1D tho will take some crop lenses at a push like the sigma 10-20 so I've heard.

[flat-planedCrank]

Quinny said:

I didn't include the 1D's as I expected anyone who can afford that level will know all about them.

But yes I believe they still have a crop factor (1.3) rings a bell so I expect that EF-S lenses won't work with them

To be extra picky "that list" Isn't full frame Only the 5D is full frame

Edited by Quinny on Wednesday 26th December 23:35

I'll be mega picky by saying that the 1ds series is also full frame





Cheers.

[MonkeyHanger]

Right then...

Canon Crop Factors. (There are some exceptions, but i'll keep it simple)

1Ds/1DsMK2/1DsMK3/5D. All Full Frame. (No Crop factor) Use EF Lenses, EF-S Lenses not compatible.

1D/1DMK2/1DMK2N/1MK3. 1.3x Crop Factor. Use EF Lenses, EF-S not compatible.

10D/D30/D60. 1.6x Crop Factor. Use EF lenses. EF-S NOT Compatible.

300D/350D/400D/20D/30D/40D. EF and EF-S lenses compatible.

[peterguk]

Thanks for all the info. guys.

Any other tips for a DSLR newbie?

I spent years with a Nikon F601 outfit so am happy with general theory etc.

[flat-planedCrank]

Quinny said:

I'll be even pickier and say that the EOS 1d Mk lll has a crop factor of 1.3

&

The EOS 1ds Mk 111 is full frame.

They both take EF lenses only though.

So we're either both right, or we're both wrong

Either way Merry Xmas & a Happy new year

Edited by Quinny on Thursday 27th December 10:49

I vote we are both right Its christmas after all !