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Author Topic: Comments on the design decisions of 24-70 II?  (Read 1961 times)

Mika

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Comments on the design decisions of 24-70 II?
« on: October 13, 2012, 11:24:33 AM »
Since some of you already have the new 24-70 II, I thought it might be a good time to post up a topic like this. My question is this: do you see that you would use the Mark II in a different way than Mark I?

I ask because what I think is that Canon improved the drawing capability by quite a margin over the old lens. Additionally, from the reviews it sounds like the wide angle side does not have that much field curvature any more (though I'm not sure whether this has been intentional as well), and color aberrations have been reduced further.

These design decisions apparently came with the following drawbacks: bokeh isn't as nice as it was with Mark I, there is more distortion, and while the minimum focus distance is the same, the reproduction factor has dropped from 3.45 to somewhere around 5.

For my style of photography, these things actually make Mark II sound less appealing (granted; I have not tried it yet). Have you noticed these differences in actual use? I have got a good use of the old lenses macro, and would not like to see that capability go so that I'd need to carry a macro lens to do same stuff in the future. As I occasionally use film, I don't welcome the increased distortion either.

What's your thoughts? Is this a step to a right direction for a general purpose zoom?

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Comments on the design decisions of 24-70 II?
« on: October 13, 2012, 11:24:33 AM »

Mt Spokane Photography

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Re: Comments on the design decisions of 24-70 II?
« Reply #1 on: October 13, 2012, 11:48:54 AM »
I don't pretend to have any inside information about the design tradeoffs that were actually made. 
Such things as distortion, curvature of field, sharpmess, CA, coma, AF speed, weight, and cost to manufacture are only a few that are typically considered, and improving one area is going to have a effect on the others.

Mika

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Re: Comments on the design decisions of 24-70 II?
« Reply #2 on: October 14, 2012, 05:47:34 AM »
I'm very much aware of that, though some of those decisions can be derived from the lens specifications.

However, the bigger question was, do you notice that you would be using the lens in a different way than Mark I?

gmrza

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Re: Comments on the design decisions of 24-70 II?
« Reply #3 on: October 14, 2012, 07:15:19 AM »
I don't pretend to have any inside information about the design tradeoffs that were actually made. 
Such things as distortion, curvature of field, sharpmess, CA, coma, AF speed, weight, and cost to manufacture are only a few that are typically considered, and improving one area is going to have a effect on the others.

I have a suspicion that Canon focused more on sharpness, with a view that other forms of distortion can more easily be addressed in software/silicon.  I suspect however that this is becoming a more general trend in lens design, to primarily address sharpness, and to concentrate less on correcting spherical and chromatic aberration optically, and rather to finish correcting these in silicon or in software (albeit at the cost of some sharpness).  This probably ties together with more of the recent cameras doing lens correction in their in-camera JPG conversion.

My initial perceptions of the lens (only since yesterday) are good, but I have not done any quantitative tests of it.  For instance, I don't know to what degree the field curvature has been addressed.
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Mt Spokane Photography

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Re: Comments on the design decisions of 24-70 II?
« Reply #4 on: October 14, 2012, 12:53:30 PM »
I'm very much aware of that, though some of those decisions can be derived from the lens specifications.

However, the bigger question was, do you notice that you would be using the lens in a different way than Mark I?
I doubt it, I do not know how the many different lens formulas they have tried affect the variables.  They try to balance all the factors, while, of course, giving maximum sharpness.  One formula may be sharp but have curvature of field, another might have more CA, and some might have more lens elements running up the cost, weight, and reducing light transmission.
How do we deduce which lens formulas they tried and what their properties were?
I would not use the MK I, I had five and did not like any, and sold them.  So any sustained use of the MK II at all would be different use.

Mika

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Re: Comments on the design decisions of 24-70 II?
« Reply #5 on: October 15, 2012, 03:16:13 PM »
Quote
I have a suspicion that Canon focused more on sharpness, with a view that other forms of distortion can more easily be addressed in software/silicon.  I suspect however that this is becoming a more general trend in lens design, to primarily address sharpness, and to concentrate less on correcting spherical and chromatic aberration optically, and rather to finish correcting these in silicon or in software (albeit at the cost of some sharpness).  This probably ties together with more of the recent cameras doing lens correction in their in-camera JPG conversion.

I think this is the case too. Spherical aberration typically has something to do with bokeh in a way that designing for the maximum MTF makes bokeh more nervous. Leaving some residual spherical aberration tends to improve the bokeh, and I suspect this has indeed been the case with the older 24-70. Increased sharpness requirements might aim for the future sensors too, too bad it tends to make bokeh worse.

Maybe people have been asking for more sharpness from 24-70, so that's what they get. Distortion and bokeh are the trade-offs then. What I don't know is whether they realized that bokeh will become worse for that. Also, for me it starts to sound that the new lens isn't as versatile as the old one, new one seems to be aimed more for people working at wide angles, while I think the older one was better overall at 35-70 mm range (the one I tend to use more). Basically, that's the reason why I have been asking whether those who own the lens have noticed a shift in their photographing habits. Call it being curious, then  ;)

Quote
I doubt it, I do not know how the many different lens formulas they have tried affect the variables.  They try to balance all the factors, while, of course, giving maximum sharpness.  One formula may be sharp but have curvature of field, another might have more CA, and some might have more lens elements running up the cost, weight, and reducing light transmission.

How do we deduce which lens formulas they tried and what their properties were?
I would not use the MK I, I had five and did not like any, and sold them.  So any sustained use of the MK II at all would be different use.

Trust me, I'm very aware of the lens design process and the trade-offs and compromises included in that. But why would the actual lens structure be of importance to this discussion? Why would the designs that weren't selected as final candidates be relevant to this discussion? We know the 24-70 mk I and mk II specifications. That's enough for me to see the differences what they choose for the actual photographing (and which I listed on the first post), which is what matters here.

So far I have actually liked Canon optical design choices (I'd actually like to buy a few for the optical guys at Canon, but chances are I'll never meet them), but the new 24-70 makes me question about the direction they are going to go next. So, from what I have seen, the people who mainly photograph landscapes do like the new 24-70. How about the event photographers?

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Re: Comments on the design decisions of 24-70 II?
« Reply #6 on: October 18, 2012, 12:26:32 PM »
The mark 1 zooming ring seems a bit tight compare to my 70-200 F4. I wonder if the mark 2 is the same.

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Re: Comments on the design decisions of 24-70 II?
« Reply #6 on: October 18, 2012, 12:26:32 PM »

Mika

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Re: Comments on the design decisions of 24-70 II?
« Reply #7 on: October 20, 2012, 01:51:58 PM »
What it comes to the zoom ring stiffness, I think they have made it intentionally so to prevent lens creep. Lens creep should not happen at all with a new 24-70 mk I, but the ring tends to become more loose over time so some of that initial stiffness will go away and you may start to see some miniscule lens creep after a couple of years of use. 70-200 F4 is remarkably smooth and easy compared to most of the zoom rings I have tried.

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Re: Comments on the design decisions of 24-70 II?
« Reply #7 on: October 20, 2012, 01:51:58 PM »