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Author Topic: Photozone's review of the EF 24-70 f/2.8L II is up  (Read 14738 times)

LetTheRightLensIn

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #45 on: September 24, 2012, 12:33:10 AM »
What? The 70-300L has a reversed focus/zoom direction? Really?

It does not.

It does have the ring placement swapped compared to many Canon zooms. I can't say it's bothered me in the slightest.

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #45 on: September 24, 2012, 12:33:10 AM »

Marsu42

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #46 on: September 24, 2012, 04:30:36 AM »
What? The 70-300L has a reversed focus/zoom direction? Really?
It does have the ring placement swapped compared to many Canon zooms. I can't say it's bothered me in the slightest.

Sorry, I mixed up "focus direction" with "focus placement" - thanks for correcting me!

M.ST

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #47 on: September 24, 2012, 06:28:38 AM »
It seems to be, that Canon has the same problems with the production as in April 2012.

I recommend this lens, because my two lenses are sharp from edge to edge in all possible focal ranges.

Some photographers that I know are not happy with their lenses, because they are not sharp from edge to edge or not so sharp as my lenses.

I test their lenses and totally agree with their opinion.

My advice:
If you hold the new EF 24-70 II in your hand test it in the complete focal range and with different apertures. If you notice any problems return it to Canon and demand a perfect one.

I don´t  accept drawbacks in this price class or above.

jpjeff

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #48 on: September 24, 2012, 07:27:09 AM »
Guys any advice on best way to test the lens?

http://www.canonrumors.com/tech-articles/how-to-test-a-lens/

Or would Reikan FoCal or SpyderLENSCAL be enough?

I have both and they take alot of time and it is quite tricky to do

DarkKnightNine

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #49 on: September 25, 2012, 02:04:25 PM »


I struggle to believe there is that much sample variation.  My hunch tells me that maybe one of the reviewers may be off the mark with their testing.   I think I will reserve judgement until the next set of reviews come through.

 
Here is a video from a few years back about Canon manufacturing a 500mm f/4 lens.  You get a idea about whats involved.  THere are three parts, this links to part 1.  You can easily find the others.
 
Canon Lens Production 1



Looking at this video, there seems to be a lot of instances where impurities can creep into the manufacturing process. I don't know if you posted this video in support of Canon or against them. My take is that I wasn't very impressed. The factory doesn't look very purified or dust free.
Canon 1DX, Canon 5D Mark III, EF 85mm F1.2L II USM, EF 100mm F2.8L IS USM Macro, EF 16-35mm F2.8L II USM, EF 24-70mm F2.8L II USM, EF 70-200mm F2.8L IS II USM, 600EX-RT Speedlites, Profoto Studio Strobes, and a whole lot of boat load of light modifiers.

Marsu42

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #50 on: September 25, 2012, 02:18:34 PM »
My take is that I wasn't very impressed.

While these lenses might seem very expensive to the average Joe like me, it has to be said that a consumer dlsr lens is not the Hubble space telescope (and even that was flawed). And shiny brochures and detailed specs might cloud the fact that it's just a normal industrial mass production - produce cheap, sell expensive.

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #51 on: September 25, 2012, 03:08:41 PM »
Those videos of how the 500mm f/4L lenses are made are quite interesting because they show that there are almost two dozen unique steps in the manufacturing process:

1. Material blending
2. Pre-fusing
3. Melted glass allows to cool naturally
4. Cut the glass into pieces
5. Fusing
6. Mixing
7. Churning
8. Clarification
9. Homogenization
10. Shape the glass into sheets
11. Shaping and pressing process
12. Grinning processes
13. Heating the glass and form its shape by pressing (by hands or by automatic machines)
14. Annealing
15. Further polishing
16. Rough grinding that produces that curved surface of the lens
17. Fine grinding
18. Polishing and surface curvuture adjustment
19. Optical inspection
20. Clean with ultrasonic washing machines
21. Alignment
22. Coating
23. The Lens assembly process itself (done by hand for Canon L lenses)

From a QC perspective, the steps outlined in Red above indicate that there is scope for variation due to human involvement. I always think of buying an 'L' lens as a bespoke product and not a commodity-type consumer one. After all, when you're expected to pay a lot of money for an object that is essentially hand-built and uses the best possible components, you have to expect some degree of variation (all manufacturing processes have tolerances - usually picked-up in the variance or standard deviations of the final goods).

Ultimately, both Nikon and Canon employ highly skilled technicians to build and assemble Professional grade lenses, and there has to be variation between these humans. I would bet a lot of money that if you were to test  a large sample of say 2,000 L lenses produced over a 90-day period and created an index of the optical performance of each lens, then plotted the frequency distribution of those L lenses, that the results might look pretty normal (bell-shaped distribution curve), but then take the same data and plot their scores (or their deviations from the mean) chronologically (as a times series plot) or by Technician you would be very surprised indeed. You may find that Technician B on average produces L Lenses with less variation than Technician D or E, or you might find with shift-work that day-shift batches are better/worse than night-shift workers etc. Or even that Assembly line 2 is better than Assembly line 1 or that for Technician A there was a 2-week spike up in August in the variance of his output - that mysteriously dropped when he returned from vacation!

Bloggers on CR often use automobile analogies, well I did quite a bit of research on BMW Motorsport before I ever bought an M-badge car and one feature of their QC process stood out - every M car produced is test-driven on the world famous Nurburgring Racing Circuit, and it is said that the test drivers can tell which Technician hand-built the engine in every car. Furthermore, they had a Chief Technician in the 1990s, who it was said could simply switch on the engine whilst the car was stationary, walk around it and listen to the sound it produced as well as press his ear up to the bodywork (and feel the vibration) of the vehicle and he could then say: "Claus assembled this one!" Urban myth? Perhaps, but it does speak volumes for the fact that even the most expensive items in the world have considerable product-to-product variation.

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #51 on: September 25, 2012, 03:08:41 PM »

Marsu42

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #52 on: September 26, 2012, 06:36:11 AM »
If you notice any problems return it to Canon and demand a perfect one.

But I don't buy lenses from Canon, it's a the most cheap shop I can find ... and this gets tricky is there was a price discount if the lens is bought together with a body. Really, @ €2300 there mustn't be this discussion and the awkwardness to look for a good sample, that's why people usually say "Don't buy Tamron".

AJ

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #53 on: September 26, 2012, 11:45:17 AM »

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=787&Camera=453&Sample=0&FLI=0&API=0&LensComp=786&CameraComp=453&SampleComp=0&FLIComp=0&APIComp=0


Thanks for the link.  The Tamron looks good, but the Canon looks really REALLY good.  Pretty darn close to perfect, actually.  I wonder if Klaus got a subpar sample.

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Re: Photozone's review of the EF 24-70 f/2.8L II is up
« Reply #53 on: September 26, 2012, 11:45:17 AM »