Which to buy? Canon 24-105 F/4 IS L or 24-70mm f/2.8L II USM?

[scottcolbath]

I was all set to grab a 24-70, but I'm now having thoughts about the 24-105. Here's the deal.

With the 24-105 on my 5D MK2 and my 70-200 on my 7D, I'd have quite a range covered. Basically 24-300mm.

With the 24-70, there would be a slight focal gap between the two.

Which of the two would you pick given my camera bodies, and why?

S.C.

[Jay Beckman]

How do you figure there's a gap? (Don't use the Crop Factor in determining focal lengths.  The actual focal length does not change!)

24-70 -> 70-200

With the 24-105, you've got a 35mm overlap.

I'd go 24-70 for the extra stop of speed (f/2.8 Vs f/4)

[scottcolbath]

How do you figure there's a gap? (Don't use the Crop Factor in determining focal lengths.  The actual focal length does not change!)

24-70 -> 70-200

With the 24-105, you've got a 35mm overlap.

I'd go 24-70 for the extra stop of speed (f/2.8 Vs f/4)

Am I missing something here? I am not exactly an expert on this, but I have been told for as long as I've been playing with DSLRs that if you're shooting with a camera with a 1.x crop sensor, you do the math to get the actual focal length when using an EF lens. Obviously, the EF-S are made just for the APS-C sensor and those would be literal focal lengths, but an EF lens actual focal length would need to be calculated based on the sensor crop.

So....Wouldn't the 70-200 on my 7D actually equate to 112-320? And the 24-105 on the full frame 5D MK2 would just provide an actual 24-105? I'd have a small gap, whereas the 24-70 on the 5D would leave me about a 40mm gap?



S.C.

[Jay Beckman]

You do not get an actual physical change in the focal length.  It's no different than if you were to crop an image yourself in Photoshop.

You get a change in the apparent field of view but if you were to shoot the same scene with the same lens on your two bodies, all you'd see is that the parts around the outside of the image from your FF body would be gone in the image from your Crop body.  The items that fit in the frame in both shots would still have the same relationship to you and to each other.

[Scott Youmans]

Scott, Jay is correct, no gap in coverage.

I've shot with both lenses although my 24-70mm was a Nikon used with a D300 and D3.  I loved the 24-70mm but was sometimes faced with running out of focal length walking around flight lines or even street shooting situations.  I have also grown used to having IS.  Although the 24-70 has a one stop advantage in the speed department the IS on the 24-105mm more than makes up for it (in some situations) and you have slightly more depth of field at f/4.  Of course sometimes you want to shoot at f/2.8 for soft backgrounds and then the 24-70 is the only way to go.  If you want to do portraits or other similar photography needing shallow depth of field etc. the 24-70mm f/2.8 is the clear winner.  On the other hand for a general purpose lens I think you'll find the 24-105 very versatile.  For absolute resolution the 24-70mm might have a slight edge.  It really depends on the kind of shooting you do.  I've had my 24-105 longer than any other piece of camera equipment not counting manual focus stuff.  Got it soon after it was introduced.

Another question comes to mind and that is do you intend to always have your 70-200 with you?  If so, the extra range of the 24-105mm becomes somewhat redundant.  

Sorry to answer your question with questions!

[Scott Youmans]

Made a correction to typo in previous post in case you read it earlier.  Fixed now.

[scottcolbath]

You do not get an actual physical change in the focal length.  It's no different than if you were to crop an image yourself in Photoshop.

You get a change in the apparent field of view but if you were to shoot the same scene with the same lens on your two bodies, all you'd see is that the parts around the outside of the image from your FF body would be gone in the image from your Crop body.  The items that fit in the frame in both shots would still have the same relationship to you and to each other.

So you are saying that things will not appear any closer with the EF on a 1.x crop body? A dog which if measured in a pic with a 400mm lens on a 7D will be the same size as the same dog measured in a pic with a 400mm lens on a 5D. The periphery will be gone since that is essentially thrown away due to the sensor not being large enough to capture it. Nothing more.

Have I got it right?

S.C.

[BillOz]

Scott,

If you have the same lens focal length say 200mm on a 1.6x crop body and on a full frame body, and you are shooting the same subject, say a dog,  from the same distance, then the dog in the crop body image will appear larger.   He will appear like you had a 200x1.6=320mm lens on the full frame body. 

Now to complicate things, usually the full frame body has more pixels, and so you can crop the image to the same size as the crop body and get some of the magnification of the crop body.  But these days with an 18 megapixel crop and a 21 megapixel full frame, the crop body subject will still be larger.   No direct easy comparison, but the crop body subject is almost always going to be larger in the image.  That doesn't mean it will be better resolution, and you do lose (gain) some depth of field as well.

[BillOz]

I have also been undecided on which of these lenses to get, but think in the end I would go with the 24-70, though I do go back and forth now and then when thinking about them.

My reasoning is somewhat as follows.

The 24-70 has a larger max aperature which is better for depth of field control, and low light.  I believe the image quality is also slightly better than the 24-105.  You use a short lens generally in situations where both depth of field and available light play more of a role than when using a longer lens.

The one advantage the 24-105 has is image stabilization, which can be significant, and help with the low light issue, but not the depth of field. 

I would use whichever lens you get on the 5D MkII, as it is full frame, so you don't bump the 24 mm to 38mm effective, and one of the advantages of the 1.6 crop 7D is it effectively increases the lens focal length, and with aviation, and many other types of photography, the longer your lens the better off you are.  So keep the big lenses on the 7D, and the shorter lenses on the 5D MkII.

My 2 cents cropped at 1.6x, so 3.2 cents.

I'm sure you'll enjoy either lens.

[Jay Beckman]

So you are saying that things will not appear any closer with the EF on a 1.x crop body? A dog which if measured in a pic with a 400mm lens on a 7D will be the same size as the same dog measured in a pic with a 400mm lens on a 5D. The periphery will be gone since that is essentially thrown away due to the sensor not being large enough to capture it. Nothing more.

Have I got it right?

S.C.

It's just as if you were cropping on the fly...

Bill pretty much nailed the whole "Reach Rig Vs Artsy Rig" way of thinking...  That's how I worked when I had three bodies (each with a different sensor)

40D = Big Reach
MkIII = Big Speed
5D = Big IQ

One other issue to consider that I don't think Bill or Scott have mentioned: FF sensors yield shallower depth of field than 1.6X Sensors.  So if you were to go with the 24-70, you can shoot shallower on the 5DMkII than on your crop body (should you ever need to take advantage of wide open @ f/2.8 )

[Scott Youmans]

Another way of looking at the crop factor situation - the image on the sensor is the same regardless of the sensor size you have. Strictly dependent on the focal length, all else being equal.  So with a full frame sensor you just have more room around the subject.  As Jay mentioned, you're just clipping off the edges when using a 1.x crop factor camera.

Imagine taking a 35mm slide and cutting a quarter inch or so off the edges of the image area.  That's all your doing with a smaller sensor camera.  The sensor is physically smaller in height and width.  The 1.6X or 1.5X factor almost makes it sound like the sensor is bigger somehow or that it magnifies the image, neither of which is the case.

The density of pixels on the sensor comes into play as well but if the two sensors, big and small, have the same density of pixels (ppi) then the object as resolved on the sensor will be of equal resolution with either sensor.  You'll just have a lot more space around the object on the large sensor.

[Scott Youmans]

Of course none of this helps Scott decide which lens to get!  It really comes down to what you want to use if for.  As has been pointed out, the 24-70 can do one thing that the 24-105 simply cannot and that is produce a somewhat softer, out of focus background.  If that's a capability you need then that settles it!

Here's an image taken with a 5D MkII with a 24-105 at f/4. Not to shabby in the bokeh department considering. Sometimes you need to shoot at f/4 even with an f/2.8 lens to get enough depth of field for the subject so f/2.8 is not always a cure all.  Not trying to promote the 24-105 necessarily, just info. Since I have a 70-200 f/2.8 I don't need another portrait lens since I'd be shooting at 70mm or higher anyway. If I were going to shoot a lot of portraits (but not weddings) I'd get an 85mm f/1.8 or 100mm f/2.  I've never used an 85mm 1.2 but I'm sure it's nice!

[scottcolbath]

For whatever reason, the principles of this still don't make sense to me. I can pick apart a TCP/IP raw trace, but can not comprehend this subjecct. 

That aside, I'll go with the 24-70 based on blind faith in my fellow AzAp gurus. 

S.C.

[Jay Beckman]

You won't be disappointed Scott...

(Although you might start to walk with a list.  There's a reason the 24-70 is nicknamed "The Brick")

[Chris Kennedy]

The new 24-70 II won't be available for a couple of months. B & H is taking pre-orders with expected availability date of April 17th.

http://www.bhphotovideo.com/c/product/843008-USA/Canon_5175B002_EF_24_70mm_f_2_8L_II.html