August 20, 2014, 09:20:13 AM

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Messages - Etienne

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16
EOS Bodies - For Stills / Re: Fun Arias rant on APS-C vs. FF
« on: July 31, 2014, 06:04:09 PM »
I have both but full frame rules as an all-round format: shallow DOF capability (even at f2.8 ) , better colors (at least in Canon), better low light performance.
As you shrink the sensor you need to improve the glass: it needs better resolution because of smaller pixel pitch, and wider aperture to achieve the same DOF.
Anyway, if there was an APS-C solution as good as full frame, but cheaper and/or lighter, I'd go for it. But it doesn't exist.

17
EOS Bodies / Re: Canon to Make a Big Splash at Photokina? [CR2]
« on: July 30, 2014, 03:15:42 PM »
Does Canon usually announce entry-level products at Photokina?  I'm curious if they will be bringing out a more competitive Rebel to counter the recent entry-level Nikon refreshes. 

I am excited about hearing what a new 7D II would bring.

I am excited too i want to see what they do with the 7D II and hopefully it is something revolutionary and gets pushed to the FF cameras like the 5d4.

Yes, but this doesn't preclude EF lenses being 'cropped'. Would be nice as a type of digital TC. However knowing Canon's marketing policies, it's almost definitely not going to happen.

I'm always lost with crop-mode on Nikon FX to DX.  Unless you want to shave your RAW file size (cough D800 cough), why crop in-camera like that?  Why not crop in post?

- A

In Camera cropping is necessary for  video, so you don't lose resolution if you want a tighter shot.

18
EOS Bodies / Re: Canon to Make a Big Splash at Photokina? [CR2]
« on: July 30, 2014, 10:34:13 AM »

A lot of 1Dx in the 7DII ... Interesting!

This is exciting and worrying .. if it's too good, I might have to open my wallet ... again  :-\
or maybe put the 5DIII up for sale.

19
Lenses / Re: New Canon L Primes, but Not Until 2015 [CR2)
« on: July 28, 2014, 10:22:48 PM »
I hope the non-L 85/2.0 IS is still coming this year!  ::)

I'll take one of those too!

20
Lenses / Re: New Canon L Primes, but Not Until 2015 [CR2)
« on: July 28, 2014, 03:46:53 PM »
The second is a new 50L in late 2015. The new lens is said to be a lot smaller and lighter, perhaps a drop to f/1.4?

Exactly what I was suggesting just a few days ago on the Photokina thread, the new consumer 50mm IS at f1.8 or even f2.0 makes way for a much better 50mm f1.4 in the same mold as the 24mm f1.4 II L - same with the 85mm, which could also go to f1.4

They would lose their bragging rights for f/1.2 primes. I do not see this scenario as probable. At least not for the 85/1.2, which is amazing lens even wide open, so why "lessen" the lens to a "mere" f/1.4.

f/1.4 is plenty, and it keeps the weight and price down a bit. I'm hoping for a 50mm with IS, equivalent quality to the 35 f/2 IS !

21
Lenses / Re: Review: Sigma 12-24mm f/4.5-5.6 DG II HSM
« on: July 23, 2014, 09:53:11 AM »
Camera's are heading to higher and higher pixel counts, so they need sharper lenses.

Lenses should be designed and bought with photographers' needs, rather than sensor specs, in mind.

I very rarely print larger than A4, which means 99.9% of the time I could do with ~8MP at 300DPI + margin for crop, so the current crop of 18MP sensors is already an overkill for me.

I'm not going to complain about rise in sensor resolution, as disks & memory cards are getting larger, faster, and cheaper all the time, but why the hell would I spend money & effort on sharper lenses & better stabilization just to get those extra pixels I don't need to begin with?

I'm sure the multiple benefits of high resolution (like cropping) have been listed a zillion times, so I'll skip that. An ultra-wide has many uses, not the least of which is landscape, and most ultra-wide shots are vastly improved by sharp resolution. It has become a point of pride with some people here that they don't "need" this or that improvement. That's shortsighted in my opinion. Anyone can opt-out of improved technology at any time, and old "good-enough" lenses are always available for you. If you are completely satisfied with what you have, good for you, you'll save money.  But the world moves on, and I prefer to move on with it.

22
Lenses / Re: Review: Sigma 12-24mm f/4.5-5.6 DG II HSM
« on: July 22, 2014, 11:47:45 PM »
I can't see using a soft ultra-wide, it's exactly the wrong direction. You'd have to shoot everything at f/11, so you'll need good lighting all the time. Camera's are heading to higher and higher pixel counts, so they need sharper lenses.

23
Canon General / Re: New Speedlite Coming? [CR2]
« on: July 17, 2014, 08:59:20 AM »
Let me rephrase that- how much cheaper will Canon be willing to price the 4X0RT anyway? (considering Canon's general inclination towards R&D roi and profit)

You don't want to hear my answer, I'm Mr. "Canon is too greedy" around here. Though I have to admit the 600rt is a very good piece of equipment, they have to get back their r&d investment and Yongnuo just showed us how not to do it with the terrible st-e3 transmitter clone.

People seem to love the YongNuo transmitter ... and it has a built in focus assist light

24
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 15, 2014, 11:03:35 PM »
Theoretical is just that and some of the more expensive lenses do get close. I think that a f/5.6 lens could be made with as good an image quality that a f/2.8 lens (both 400mm) has at f/5.6 for less money (than the f/2.8 lens) because of the smaller pieces of glass used. They would have the same MTF values at f/5.6. There would, however, be more vignetting for the f/5.6 lens because of the smaller pieces of glass.
However, to make the lens cheaper the f/5.6 lens may not be as good as f/2.8 stopped down to f/5.6.

To improve a f/5.6 lens (to the level of the f/2.8 lens stopped down to f/5.6) could involve more expensive glass types for example. These expensive types are used in the f/2.8 lens. I suspect an improved (resolution-wise) 400/5.6 lens would involve selecting more expensive glass that would drive up the price. I think this is what we are seeing with many of Canon's lenses as they get updated. They could probably build several different 400/5.6 lenses with different price points according to the types of glass used but this is impractical. The old lens will provide a lower price point option so long as it says in production.

Understanding resolution is not a simple topic. The Rayleigh Criterion in the reference I gave above is the "textbook" example. I got this in a class I took in microscopy decades ago. In this next reference (link at end of this statement) the authors argue that this is not good enough for digital. It is very long but if one scrolls down and looks at the tables (the resolution numbers in the columns go up (apertures decrease in size as one goes down) in each table but the values vary according to criterion - going across in the table (for a given aperture)) it is obvious that the maximum theoretical resolution (i.e., diffraction limited) at f/2.8 is greater than f/5.6
link: http://www.luminous-landscape.com/tutorials/resolution.shtml


Theoretically that is obvious, from a practical standpoint aberrations and mp limits cut in way before that when wide open for us camera users and the lenses we actually have available. Your assumption earlier was "assuming similar correction for lens aberrations", it is more than four times more difficult, many would say sixteen times, to manufacture a 400 f2.8 than a 400 f5.6 with the same optical aberrations.

Theory ends when "limited" purchasing options are all we have.


The 400F5.6 is SHARPER in the corners than the 400F2.8...

There is theory, and then there is practice... Yes, in theory, a F2.8 lens could be made sharper than a F5.6 lens, but given the limited precision of manufacturing (it is not perfect and you can not polish off fractions of atoms) and the aberrations in glass, in the real world the problem becomes how to make that F2.8 lens as sharp as an f5.6 lens.

When we are comparing the two, you have to be comparing similar materials and similar designs. The 400F5.6 is a 20+ year old design and used UD elements. The 400F2.8II lens is just a few years old and uses fluorite elements... it was designed with better software and it is manufactured to higher tolerances. If you used that same level of technology/materials on a new 400F5.6 it will be noticeably sharper than the F2.8 version.

Also, with the same design, because of the larger elements, there is much more thickness of glass for the light to pass through in the F2.8 lens. This has the effect of both reducing light and increasing the odds of hitting an aberration. In theory, the glass is perfect. In the real world, it has flaws.


Very good points!

There are such a great many considerations. At the end of the day, I would love an updated, light weight 400 5.6L IS at $1999 or less! It's a lens I could afford, and carry with me.

25
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 15, 2014, 06:16:06 PM »
One reason for the big whites' high resolution property is that lens resolution is a function of diameter; a larger diameter lens (for a given focal length larger aperture lenses have larger diameters) will resolve more than a smaller diameter lens assuming similar correction for lens aberrations. See http://en.wikipedia.org/wiki/Optical_resolution and scroll down to lens resolution. There are other aspects of resolution as well that are discussed in the article. Lens aperture is just one part.


I don't believe it and I don't care. I would definitely consider a 400mm/5.6 lens with 4-stop IS and IQ at least as good as the current 400mm/5.6 ... if price was less than USD/€ 2000 and would not waste a single thought, whether or not a 400/2.8 II IS would offer still marginally better IQ @ f/5.6 ... or not.


You are right not to believe this and not to care. The original post is a bit misleading. From the wiki page:

"The ability of a lens to resolve detail is usually determined by the quality of the lens but is ultimately limited by diffraction. "

and

"Only the very highest quality lenses have diffraction limited resolution, however, and normally the quality of the lens limits its ability to resolve detail." This is the case for the lenses that mere mortals can afford. Since accurate design and production of a large aperture lens is much more difficult, the main difference you will see is light gathering ability and shallow DOF, not necessarily resolution. This reveals itself in the fact that most lenses get sharper as they are stopped down a bit : it is the aperture size used to take the image that limits the resolution that the lens can provide, not the maximum available aperture of the lens. A perfectly designed and built lens should perform worse as the aperture is reduced, but in real life, this does not happen. Reviewers of the 400 2.8L IS II say that the IQ does not improve as it is stopped down, but it doesn't get worse either. Maybe the sensor can't pick up the differences.

My bet is that Canon could design and build a 400 5.6L IS that could produce images every bit as good as the 400 2.8L IS (stopped to 5.6), of course much lighter and cheaper. Light and cheap means you're more likely to have it with you.

26
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 15, 2014, 01:07:09 PM »
And yes, there is no technical reason why canon could not ewuip the 400/5.6 with IQ as is with a current day 4 stop IS with 3 modes (full, panning, tripod sensing) and sell it at USD 1999,-

Its only freaking "marketing differentiation".

I might jump at this if it's fully usable wide open. Note that it must completely blow away my 100-400 @ 400mm.

Wow, I was a bit surprised for a minute to see that quote attributed to me.
I don't think a 400/5.6 IS will cost $ 1999, unfortunately :(

It wouldn't be worth much more than $1999 ... maybe that's why Canon hasn't produced one. Even the 100-400 won't be much past $2500, and it will have to rock at 400mm to be worth it.

27
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 15, 2014, 10:41:36 AM »
There is no reason why the 400F5.6, in an updated version, can't have the same IQ as the 400F2.8. It's that full stop faster that you pay so much for.

For example, the 24-70 F4 and the F2.8 are similar in IQ, but twice as much for a half stop.....
The 70-200 F4IS and F2.8IS are similar in IQ, but twice as much for a half stop....

Not to sound too pedantic, but the difference between f/5.6 and f/2.8 is two stops, not one. (Which only further reinforces your point.)

That's not pedantic. It needed to be said, or the author might have continued to make this mistake.

There's also a reason an f/5.6 lens can't be as sharp as a really good f/2.8 lens - diffraction.

Diffraction does not affect FF until around f/11. Diffraction doesn't even affect APS-C until f/8 . An f/5.6 lens can be every bit as sharp, or sharper than a f/2.8 lens. Large aperture does not necessarily mean sharper images, even stopped down. Just look at the Canon 50 f/1.2L, which is not as sharp as the 50 f/1.4 at comparable apertures.

28
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 15, 2014, 12:26:29 AM »
There is no reason why the 400F5.6, in an updated version, can't have the same IQ as the 400F2.8. It's that full stop faster that you pay so much for.

For example, the 24-70 F4 and the F2.8 are similar in IQ, but twice as much for a half stop.....
The 70-200 F4IS and F2.8IS are similar in IQ, but twice as much for a half stop....

Not to sound too pedantic, but the difference between f/5.6 and f/2.8 is two stops, not one. (Which only further reinforces your point.)

That's not pedantic. It needed to be said, or the author might have continued to make this mistake.

29
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 13, 2014, 04:01:52 PM »
I wish it would be 200-500, and lighter

x2

I wish Canon would release 500/600mm for the common mortals

My bag can get pretty heavy. I think I'd even prefer a 200-400 and keep it as light as possible, 800g maybe?

30
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 13, 2014, 10:45:25 AM »
I don't understand why they don't make it a 70-400 or 80-400 to have a less big gap between this lens and their 24-70's. You see at Nikon and Sony that there is no quality loss with these extra 20/30mm, so why? To keep the original?  :P  For me, the 70-100 range is important, on FF as well as on crop.  :) They make you buy an 85mm or an 70-200mm.  :-X

Does anybody really need every mm covered without gaps? Sure it can be nice, but I find the 16-35 and 70-200 combo extremely versatile. 35-70 not covered ... So what? There is no way that you can always have the right lens on the right camera at the right time. You either have to use a superzoom, and accept lower IQ, or use two or more cameras simultaneously. If you really need instant versatility and high IQ, then use the 24-70 2.8 on one body, and one of the L tele-zooms on another. Of course cost and weight could be problematic.

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