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Messages - Don Haines

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46
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 15, 2014, 10:10:51 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.

47
Lenses / Re: Year of the lens....a joke....?
« on: July 15, 2014, 08:28:45 PM »
It is the year of the lens...

but unfortunately for Canon, the lens is the Tamron 150-600......

48
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 15, 2014, 07:10:04 PM »
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.


Easily:

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=278&Camera=453&Sample=0&FLI=0&API=0&LensComp=327&CameraComp=453&SampleComp=0&FLIComp=0&APIComp=3

HEY!
This is an emotional argument.... common sense and logic (and particularly data) have no place :)

49
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 15, 2014, 10:08:57 AM »

F/2.8 to f/4 is a full stop. :-)


Obviously, I should not post when half asleep.... OOPS!!!

50
Canon General / Re: Canon PowerShot SX60 HS Update [CR2]
« on: July 15, 2014, 09:18:22 AM »
I wonder if this will be the introduction of DPAF to p/s cameras?

Would be nice, but I seriously doubt it.

My biggest hopes for this camera are:

  • Dramatically improved EVF optics.  The SX50 optics have a major field curvature issue.
  • The lens (including IS) is at least as good as that in the SX50 (which is pretty good).
  • The video performance gets a good upgrade (better quality, 60p FHD available).
agreed!

I am amazed at how good the SX-50 is, considering what it does..... Give it a better EVF and make the buttons less sensitive (or better yet, a lockout switch) and you would have a huge lead in the superzoom market.

51
Notice that the patent was filed in December of 2012. So they've had over a year and a half to work on it, plus whatever time they spent before filing. So it's possible it will be included in a 7D2 this fall.

I'd expect Canon to announce a prototype, and show off the benefits of their technology, as they have in the past, before actually using it in a product. There certainly isn't any guarantee that would happen, but it doesn't feel like the technology is ready yet. I expect more patents on the technology, and a prototype test, before we actually see a competitive layered sensor in a DSLR.
What about a P/S camera with the technology? That would be a lot safer way to introduce it.....

52
Canon General / Re: Canon PowerShot SX60 HS Update [CR2]
« on: July 15, 2014, 08:57:18 AM »
I wonder if this will be the introduction of DPAF to p/s cameras?


53
EOS Bodies / Re: DSLR ? - thinking out loud ....
« on: July 14, 2014, 11:06:34 PM »
Since we're speculating...

7 years down the road your pro/semi-pro camera will not only be mirrorless, but will have no built-in display and limited controls.  Instead, it will have a dock for your smartphone, which will serve as the control panel and view screen.(*)

(*) Not an actual prediction, for entertainment purposes only.
actually..... I would love it if I could use the Wi-Fi on the camera to connect to a smartphone or tablet and have the device act identically to the screen on the camera, or in the case of a tablet, have all the controls at your fingertips...

Im sure you can already do that...
Check 6D plus EOS app on your smart phone...
Of course it isn't perfect but it can do what you want...
That's the first "kick at the cat".... I expect future versions to be better and we will probably see this on all the new DSLRs and mirrorless cameras from this time on....

54
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 14, 2014, 11:04:08 PM »
Canon could sell a million of these if they don't hold back and just give us sports/wildlife people a great lens at a decent price.

1998 -2014, after 16 years you would think that this newer version would be much improved on what was already a decent lens.

I have to wonder if they're trying to protect the Big Whites. The 400f5.6 prime has arguably superior IQ to some of the old big whites, and upgrading something like that might look a little unbalanced.
Maybe they wanted to wait until they had all the version II supertelephoto lenses out before releasing a budget option that performs on a similar level.

Just out of curiousity, how do would you define, "on a similar level"?
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....

by that logic, I would expect a 400F5.6 similar in IQ to the 2.8.... but around 1/4 the price. Realistically though, expect 1/3 the price...

55
Canon General / Re: Canon PowerShot SX60 HS Update [CR2]
« on: July 14, 2014, 08:51:09 PM »
Well, my SLR lens kif has a 1500x range.

Looking forward to hearing about this one.
Impressive! 1500X!

My kit has a 60X range.... From 10mm to 600mm... 

You must have some interesting lenses......

Full frame fisheye to 2800mm telescope plus 2x TC on 1.6 crop.

Forgot the telescope and the 2X Barlow.... Make my range 10-4000 mm, or 400X.... But I must confess that I have not been able to hand hold the telescope, nor have I been able to slip it into my sweetheart's camera bag without her noticing it....

So, you have a C8?
Yes, good guess!

56
Canon General / Re: Canon PowerShot SX60 HS Update [CR2]
« on: July 14, 2014, 07:21:59 PM »
Well, my SLR lens kif has a 1500x range.

Looking forward to hearing about this one.
Impressive! 1500X!

My kit has a 60X range.... From 10mm to 600mm... 

You must have some interesting lenses......

Full frame fisheye to 2800mm telescope plus 2x TC on 1.6 crop.

Forgot the telescope and the 2X Barlow.... Make my range 10-4000 mm, or 400X.... But I must confess that I have not been able to hand hold the telescope, nor have I been able to slip it into my sweetheart's camera bag without her noticing it....

57
It sounds like Canon is identifying and solving a number of issues with layered sensors. Given that, and given that their patent filings are still being published, I am not sure we'll see a layered sensor with the 7D II. The issues would need to be worked out first. It's possible all of these were filed a 18-24 months ago, and the technology is ready, but there could also be ongoing work.

I'm still waiting for a Canon patent that shows they figured out how to reduce noise and increase dynamic range in a layered sensor. I think that would make...well...everyone's day. :D

It's intriguing that Canon is working on a layered sensor, though. At the very least, it gives some hope for the cameras that come after the 7D II.
The 7D2 is obviously a mirrorless APS-H multilayer sensor camera that is tightly integrated with the Microsoft Surface tablets... :)

That would be nice...especially if it has 120 beautiful megapixels. :D
Oh yes, I forgot.... QUAD pixel multilayer pixel technology where each sub- pixel is individually readable.... For a cool 480 megapixel resolution..... This improvement brought to you from the good folks at Sandisk and at Seagate.....

58
Canon General / Re: Canon PowerShot SX60 HS Update [CR2]
« on: July 14, 2014, 07:10:40 PM »
Well, my SLR lens kif has a 1500x range.

Looking forward to hearing about this one.
Impressive! 1500X!

My kit has a 60X range.... From 10mm to 600mm... 

You must have some interesting lenses......

59
Lenses / Re: Canon EF 100-400 f/4.5-5.6L IS II [CR1]
« on: July 14, 2014, 01:46:04 PM »
I am sticking with my non-stabilized 400mm f/5.6L until I can afford an f/4 supertelephoto.. I would not advise beginning birders to start with a non-stablized lens. unless they have lots of patience.
I keep hoping to see an updated version of that lens..

Yes, IS would make all the difference.
not only that, but the improvements in IQ from the series 1 to series 2 big whites are truly astounding. As someone who has been into photography for more than 40 years, I find the quality of the recent lenses astounding. A lot of people fixate on sensors, but the glass is whats makes it all possible.....

60
It sounds like Canon is identifying and solving a number of issues with layered sensors. Given that, and given that their patent filings are still being published, I am not sure we'll see a layered sensor with the 7D II. The issues would need to be worked out first. It's possible all of these were filed a 18-24 months ago, and the technology is ready, but there could also be ongoing work.

I'm still waiting for a Canon patent that shows they figured out how to reduce noise and increase dynamic range in a layered sensor. I think that would make...well...everyone's day. :D

It's intriguing that Canon is working on a layered sensor, though. At the very least, it gives some hope for the cameras that come after the 7D II.
The 7D2 is obviously a mirrorless APS-H multilayer sensor camera that is tightly integrated with the Microsoft Surface tablets... :)

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