February 28, 2015, 04:06:56 PM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - Radiating

Pages: 1 ... 8 9 [10] 11 12 ... 23
Canon WANTS diffraction to be a limiting factor so that they can remove the AA filter.

If you look at a sharp lens at f11 like a super telephoto and a soft lens at f/11 the sharp lens looks sharper despite being at the diffraction limit.

What 24MP does is it allows the whole system to be sharper due to a weaker AA filter. Diffraction is the best AA filter on earth, current ones degrade the image by 20% which is a lot.

Where do you get that 20% figure? I can't say I've experienced that with anything other than the 100-400 @ 400mm f/5.6...however in that case, I presume the issue is the lens, not the AA filter...

MTF tests of the D800 and D800E back to back

Canon WANTS diffraction to be a limiting factor so that they can remove the AA filter.
If the AA filter is an expensive/complex component, increasing the sensel density until diffraction takes care of prefiltering is definitely one possible approach.
What 24MP does is it allows the whole system to be sharper due to a weaker AA filter. Diffraction is the best AA filter on earth, current ones degrade the image by 20% which is a lot.
Diffraction is dependant on aperture, and not a constant function. In practice, one never have perfect focus (and most of us dont shoot flat brick-walls), so defocus affects the PSF. Lenses and motion further extent the effective PSF. The AA filter is one more component. I have seen compelling arguments that the total PSF might as well be modelled as a Gaussian, du to the many contributors that change with all kinds of parameters.

Claiming that the AA filter degrade "image quality" (?) by 20% is nonsense. Practical comparisions of the Nikon D800 vs D800E suggests that under some, ideal conditions, the difference in detail is practically none, once both are optimally sharpened. In other conditions (high noise), you may not be able to sharpen the D800 to the point where it offers details comparable to the D800E. Manufacturers dont include AA filters because they _like_ throwing in more component, but because when the total, effective PSF is too small compared to pixel pitch, you can have annoying aliasing that tends to look worse and is harder to remove than slight blurring.


You can't compare an unsharpened D800E image to a sharpened D800 image, that's not how information processing works.

The AA filter destroys incoming information from the lens, irreversibly. Sharpening can trick MTF tests into scoring higher numbers, but that is besides the point.

Yes diffraction changes with aperture but if you always shoot below f/5.6 you can ditch the AA filter without consequence, and those images shot below f/5.6 would be sharper than those taken with the same camera with an AA filter.

Canon WANTS diffraction to be a limiting factor so that they can remove the AA filter.

If you look at a sharp lens at f11 like a super telephoto and a soft lens at f/11 the sharp lens looks sharper despite being at the diffraction limit.

What 24MP does is it allows the whole system to be sharper due to a weaker AA filter. Diffraction is the best AA filter on earth, current ones degrade the image by 20% which is a lot.

Lenses / Re: Canon EF 12-24 f/2.8L [CR1]
« on: February 28, 2013, 11:48:58 PM »
Personally, it would be much more useful for me if Canon came up with 16-35 f/2.8 MkIII with sharpness in line with 24-70 II and 70-200 f2.8 II, as well as a real good 35 mm end..

+1....now you're talking!


Agree 100% I would rather have a 16-35mm Mk III or even better a 16-35mm f/2.8 IS (there is a nikon patent for this that promises superior IQ to the 14-24mm even).

Give us that.

Lenses / Re: What are Canon's sharpest lenses?
« on: February 26, 2013, 06:39:37 PM »
The difference  between the 100mm Macro and the 24-105mm isn't that significant.

Canon's sharpest lenses are in order (of sharpness wide open):

200mm f/2.0 IS
24mm f/3.5 TS-E II
180mm f/3.5 Macro
300mm f/2.8 IS II
400mm f/2.8 IS II
500mm f/4.0 IS II
600mm f/4.0 IS II
70-200mm f/2.8 IS II
40mm f/2.8 STM
70-200mm f/4.0 IS
90mm f/2.8 TS-E

The 100mm Macro doesn't make it on this list but is very close to the 90mm TS-E.

Lenses / Re: Why aren't zoom lenses faster than 2.8?
« on: February 25, 2013, 01:16:12 PM »
I resized and re-uploaded the photo as the link doesn't work for embeding unless it's in your cache.

Hillarious though!

Personally I would like to see the following lenses from Canon:

20-35mm f/2.0
35-70mm f/2.0
70-160mm f/2.0

These lenes would all be possible as they are aproximately 2x zooms and would have 82mm filter sizes

EOS Bodies / Re: Patent: Canon EF 14 f/2.8 with Flourite
« on: February 25, 2013, 01:06:17 PM »
This is the 2nd time that a f/2.8-4.0 wide angle zoom has been mentioned.

This is a patent for an EF-S or EF-M  17-35mm f/2.8-f/4.0 lens

And two 14mm f/2.8 lenses.

The current 14mm f/2.8 I and II is a joke especially with the Samyang 14mm f/2.8 out there which in my experience owning all 3 the Samyang is the winner, and you barley need to focus on such a wide lens anyways.

The 14-24mm f/2.8 is an absolute joke especially compared to the 14-24mm f/2.8 from nikon or if you are willing to sacrifice fov the 17mm TS-E is so much better. I would pick any of those lenses before I went with Canon's one.

Anyways this patent also brings up an interesting idea, a 14-30mm f/2.8-f/4.0 lens. That's something I could get behind.

Lenses / Re: Canon Cine vs. L lens video. Hilarious
« on: February 24, 2013, 05:37:56 PM »
Some of the funniest yet informative comparisons  ;D


Ah yes, badge engineering. Canon is by far the most ridiculously greedy company in photography.

Lenses / Re: Why aren't zoom lenses faster than 2.8?
« on: February 24, 2013, 01:39:26 AM »
In 35mm terms, its 6.1-30.5/1.8-2.8 lens is the equivalent of a 28-140/8.3-12.9 lens. Nothing too special.

Don't want to go off topic, but in 35mm terms it is still an f/1.8 - 2.8 lens.  It might have an equivalent field of view as a 28-140mm lens.  But the shutter speed is based on the f/1.8 to 2.8 aperture, which is pretty good.  The equivalent background (or lack of) is what you'd expect from a 6.1 - 30.5mm lens (which is largely independent of sensor size).  That is, you'd have similar background blur at 30.5mm at f/2.8 on G15 as you would with a 16-35mm zoomed to 30.5mm at f/2.8 on a 5Diii.  And in dark shooting conditions, shooting macro, or when capturing action with the fastest possible shutter speed, the ability to have more in focus for a given aperture is sometimes just as important.  (And besides, in post production it is easier to blur a background than add more detail in).

In a round about way, just trying to say that the aperture range of a lens should be viewed independently of sensor size.  From there, most sensible photographers can use their own judgement as to whether a particular system/sensor size is suitable for their purpose.  Need more background in focus, shoot m43 or the G15.  Need more background blur, shoot medium format (or adjust in post production).  Need it just right, shoot full frame.

Imagine this scenario - Canon releases an EF-S 400mm f/4 with image quality, build and price equivalent to the EF 400mm f/5.6.  Even though some might say it is still a "f/5.6 equivalent", most people would instantly see the benefit of the faster aperture.

People have been misled by this insane nonsense for years.

The "35mm equivalent" is what is really important and nothing else.

From a physics perspective the "35mm equivalent" is capturing identical information. What really matters is the geometry of the light hitting the sensor:

Generally the technical difficulty of achieving a particular geometry is INDEPENDENT of sensor size, meaning it's equally difficult to create a 17-55mm f/2.8 IS lens as it is to create a 24-105mm f/4.0 IS.

The front element of a 1/1.7" sensor lens that is 8-30mm f/0.3 lens would be 11.4 inches, and so would the front element of a 35mm sensor that has a 28-140mm f/1.8 lens.
Going back to the 35mm equivalent discussion, consider this:

On 7D compared the the 5D Mark III

The sensor is 1.6 x 1.6 times smaller.

35mm equivalent aperture - Multiply by (1.6 x 1.6 / 2 ) (an f stop is a base 2 log, so we divide by 2 to multiply between base 10 and base 2 if you were wondering, this just converts the number systems, nothing else)

35mm equivalent focal length - Multiply by 1.6

35mm equivalent ISO or light sensitivity - Multiply by (1.6 x 1.6) (bet you haven't heard of that,  but if you do the math the 7D's sensor amplifies the signal 1.6x1.6 times more at a given ISO than the 5D3)

The point is that people are often misled by manufacturers changing the geometry of a camera system, particularly putting in small sensors and then claiming otherwise impressive performance numbers which are incredibly misleading because you are measuring them on a different scale.

It's like saying:

I have a million dollars, and then failing to mention these are Zimbabwe dollars worth $20 not, American dollars.

Yes aperture ISO and focal length are fixed numbers, but so are monetary figures, and the most important thing even the most basic dealing of currency has is WHAT currency you're dealing with, and 99% of people require an "equivalent" frame of refference to understand foreign currency or need to do a conversion. Likewise with cameras, geometry (type of currency) is the most important thing when dealing with the performance of a camera system, and the first thing anyone needs to do is bring up a conversion to the local frame of reference, APS-C 35mm, whatever.

To respond to your post though, there is NO benefit to a 1 stop faster aperture on APS-C sensor vs full frame because they (more than) cancel each other out. You don't stop action any quicker at all, whatsoever, because remember the ISO is skewed too, so all you're doing is just turning up the ISO sensitivity in a roundabout way. You have been misled into thinking there is a benefit.

Lenses / Re: Will Canon step up to Zeiss with a 55mm 1.4L?
« on: February 23, 2013, 09:34:25 PM »
Canon is not in competition with Zeiss.  Zeiss sells very nice manual focus lenses to those with deep pockets. 
Canon is and has always been about mass production of cameras and lenses where they target value for the dollar.  By keeping prices down, they are able to turn out high volumes of lenses, and spread the very high cost of tooling and development over many lenses.
Zeiss isn't interested in that market, they know they can't compete at the price Canon charges.  They have their niche and do well with it.

Honestly if Zeiss simply had flawless autofocus I bet that their sales would increase 100 fold.

Lenses / Re: Why aren't zoom lenses faster than 2.8?
« on: February 23, 2013, 09:30:22 PM »
How come the G15 is a 1.8-2.8 and doesn't weigh a 100lbs? I actually wouldn't mind a variable aperature zoom like the G15's. why don't they do that?

Most photographers have a huge misunderstanding about this issue. Simply put the bigger the sensor is the bigger the lens, and the bigger the sensor and lens, the more light you get falling onto the sensor.

That f/1.8-f/2.8 lens on the g15  equivalent both in the amount of light it gathers and apparent background blur, and in every way that matters to a full frame:

f/10-f/16 lens.

Much less impressive.

To actually be equivalent to an f/1.8 lens on full frame the G15 would have to have an f/0.3 lens, which if using the same optical design would have a 29 centimeter front filter thread (11.4 inches in diamiter). It would look something like this in dimensions:

Lenses / Re: Will Canon step up to Zeiss with a 55mm 1.4L?
« on: February 21, 2013, 11:07:22 PM »
Would you be willing to drop $4k on a 55mm Canon lens?
Reading between the lines, that seems to be the expected price for the ZE beauty.

I already own 7 ZE lenses and this is way too rich for my blood.

I'd be willing to easily drop 4k on the Zeiss 55mm 1.4 if it had half decent USM autofocus. My style of shooting requires autofocus, and I'd love to complete my prime collection with such a lens.

All I want is the best f/2.8 zooms and the best f/1.4 primes covering 21mm to 200mm.

Lenses / Re: Why aren't zoom lenses faster than 2.8?
« on: February 21, 2013, 03:58:45 AM »
The Canon. 25-100mm lens was a cinema lens designed for a format that was much smaller yet was very heavy, about the size if a 70-200mm f/4.0 is. The sensor size was around 1/4 of full frame so while yes such a lens is possible it would be huge and expensive.

Say if you wanted a 28-85mm f/2.0. It would cost at least $10,000 based on Canons manufacturing costs for lenses of similar size, weigh 4-6 lbs and would use 120mm filters, and be over 12 inches long.

The market would be so small for such a lens Canon would likely change $20,000 or more.

Simply put such a product would be very convention defying.

You can also buy a number of f/3.5 zooms for medium format cameras which are equivalent for f/2.2 lenses on full frame. Leica makes one like that, that's equivalent to a 20-60mm lens.

Personally I think a 70-200mm f/2.0 zoom for 7k is realistic and would sell.

EOS Bodies / Re: Canon EOS 7D Mark II Spec List [CR2]
« on: February 20, 2013, 06:09:36 PM »
Just an FYI regarding all this talk of too much resolution.

Tests have shown that even the best APS-C lenses are limited to around 20 megapixels of resolution, regardless though there are some benefits to more pixels, namely:

Better de-mosaicing, ideally each pixel in a photo should have 4 pixels behind it (1 red 2 green and 1 blue) as current photos are done with false color and the bayer pattern naturally limits resolution to around 90% of what it should be.

Less interference from anti-aliasing filters, this is actually a huge deal and can increase lens resolution by 20%.

Better color gradiation and tones.

The disadvantage to more resolution is bigger file sizes (less of an issue with S_RAW (which Nikon inexplicably doesn't have).

24 Megapixels is the perfect resolution for an APS-C camera and 28 megapixels is the perfect resolution for a full frame camera with current lens designs.

Lenses / Will Canon step up to Zeiss with a 55mm 1.4L?
« on: February 19, 2013, 03:51:19 AM »
It seems Zeiss's new 55mm f/1.4 lens which promises to be as sharp as current Canon 50mm lenses are at f/5.6 wide open is making a lot of news (50mm lenses tend to fall far behind other primes for image quality, delivering what 24mm and 85mm primes deliver wide open at f/4.0). In my own quest for a great 50mm prime I've looked at every 50mm prime thats ef compatible or ef adaptable made since 1970 and all deliever this mediocre image quality (though being 55mm is likely key in allowing the iq).

So Zeiss has cracked the high quality normal prime mystery that has eluded all other manufactures for decades.

The question is, now that the cat's out of the bag, will Canon fire back with a 55mm 1.4L?

If you're interested here's a video describing the new lens. It's worth watching.


Third Party Manufacturers / Re: To anyone waiting for a new 100-400L...
« on: February 18, 2013, 10:58:24 PM »
Sony is getting ready to release a new 70-400, and it looks like the price of the new lens will be a whopping $3000!

You can see a blurb about the price at the bottom of this post: http://www.sonyalpharumors.com/sr5-full-a58-and-nex-3n-specs/

I wonder what the eventual 100-400L successor will cost  :o

The 70-400mm I is one of the worst lenses ever made. I doubt they can put out something decent.

Pages: 1 ... 8 9 [10] 11 12 ... 23