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Messages - dilbert

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1
Third Party Manufacturers / Re: Samyang Teases Some New Lenses
« on: April 18, 2014, 02:06:35 PM »
When is someone going to make a wide angle lens (16 - 35 or there abouts) for Canon EF mount that doesn't suck, doesn't cost the earth and has auto-focus?

Tokina makes a 16-28mm F2.8 quite interesting, which costs $629.


The Tokina 16-28/2.8 is an EF-S lens, not EF.


No it isn't. The 11-16/2.8 is EF-S (But mounts on full frame). The 16-28 f2.8 is full frame.


But that has the bulbous front element which means using it with filters is a PITA.

Plus photozone doesn't think much of its optics...

http://www.photozone.de/canon_eos_ff/595-tokina162828eosff

2
Third Party Manufacturers / Re: Samyang Teases Some New Lenses
« on: April 18, 2014, 01:02:54 PM »
When is someone going to make a wide angle lens (16 - 35 or there abouts) for Canon EF mount that doesn't suck, doesn't cost the earth and has auto-focus?
Tokina makes a 16-28mm F2.8 quite interesting, which costs $629.

The Tokina 16-28/2.8 is an EF-S lens, not EF.

3
Third Party Manufacturers / Re: Samyang Teases Some New Lenses
« on: April 18, 2014, 09:53:17 AM »
When is someone going to make a wide angle lens (16 - 35 or there abouts) for Canon EF mount that doesn't suck, doesn't cost the earth and has auto-focus?

4
I'm more interested in a future Sigma 85mm Art 8)

+1

5
Wonder if this lens will be eligible for Sigma's "mount conversion" service?

I'm surprised that so far nobody has said DxO's results are meaningless because they don't represent bokeh in their tests results anywhere! But at least the first post on this thread doesn't disappoint with the expected putting down of DxO.

When DxO get a Nikon mount copy of this lens, I think we'll see a much better representation of its capabilities. In at least one score, the "megapixel" thing, the scores are obviously limited to what Canon cameras can provide.

Compared to the 50/1.2L

NameCanon 50/1.2LSigma 50/1.4A
Camera5D Mk III5D Mark III
Sharpness1821
Transmission1.4TStop1.7TStop
Distortion0.4%0.1%
Vignetting-2.4EV-1.5EV
Chr Aberration20µm6µm

Wow, that's about as cherry picked and biased a comparison as I've ever seen. Do you even try to be objective?

No honey, I don't. If I was objective then you'd have nothing to post about and then you'd get bored.

6
Lenses / Re: Sigma vs Zeiss vs Canon
« on: April 18, 2014, 01:18:02 AM »
@Dilbert: I refer you to Neuro's answers for all the spherical aberration stuff. Canon DOES purposely leave in spherical aberration by design, as it is a desirable effect in many circumstances.

As for your assuming, you assume that people are trying to justify what Canon does, when in actuality people are simply explaining what Canon does. You assume that people here "worship" Canon, when in fact some people are simply fans, others are simply customers and might otherwise not care about the brand. You assume a whole hell of a lot about people here man, and then you lash out at them with thinly veiled hostility and nasty words based on your INCORRECT assumptions.

All I'm saying is...might not want to assume, you would look like less of a donkey's rear end in the end.


Well I asked a collection of questions (to you) in this post:
http://www.canonrumors.com/forum/index.php?topic=20498.msg387881#msg387881
but you have not answered. Should I take from this that you do not wish to enlighten me with information and thus leave me in a place where I can only but make assumptions?

7

Not that it will help the 50L much, but you might want to report the data for the two lenses tested on the same camera, instead of different cameras.  Either drop the Sigma to 18 P-Mpix for the 1DsIII, or raise the 50L to 16 P-Mpix for the 5DIII.  Or just leave it alone if you'd prefer to artificially bias the data in favor of the point you're making.

Thanks for bringing it to my attention. Fixed

You'd think DxO could code the site so the same camera was selected by default.  But no...

Their website is a PITA to navigate and however they do their indexing is a mystery ...

... it may also mean that the majority of those that use the 50/1.2L for photography do so with a 1Ds Mk III.

8
Lenses / Re: Sigma vs Zeiss vs Canon
« on: April 18, 2014, 01:11:16 AM »
@Dilbert: I refer you to Neuro's answers for all the spherical aberration stuff. Canon DOES purposely leave in spherical aberration by design, as it is a desirable effect in many circumstances.

How many of Canon's lenses have spherical aberration specifically designed into them?

And perhaps a better question to ask, if Sigma (and Zeiss?) can design sharp lenses that produce pleasing bokeh without spherical aberration then why can't Canon?

Quote
As for your assuming, you assume that people are trying to justify what Canon does, when in actuality people are simply explaining what Canon does. You assume that people here "worship" Canon, when in fact some people are simply fans, others are simply customers and might otherwise not care about the brand. You assume a whole hell of a lot about people here man, and then you lash out at them with thinly veiled hostility and nasty words based on your INCORRECT assumptions.

What has this got to do with lenses???

Quote
All I'm saying is...might not want to assume, you would look like less of a donkey's rear end in the end.

What concern of yours what I do or do not look like? hmm?

9

Not that it will help the 50L much, but you might want to report the data for the two lenses tested on the same camera, instead of different cameras.  Either drop the Sigma to 18 P-Mpix for the 1DsIII, or raise the 50L to 16 P-Mpix for the 5DIII.  Or just leave it alone if you'd prefer to artificially bias the data in favor of the point you're making.

Thanks for bringing it to my attention. Fixed

10
Wonder if this lens will be eligible for Sigma's "mount conversion" service?

I'm surprised that so far nobody has said DxO's results are meaningless because they don't represent bokeh in their tests results anywhere! But at least the first post on this thread doesn't disappoint with the expected putting down of DxO.

When DxO get a Nikon mount copy of this lens, I think we'll see a much better representation of its capabilities. In at least one score, the "megapixel" thing, the scores are obviously limited to what Canon cameras can provide.

Compared to the 50/1.2L

NameCanon 50/1.2LSigma 50/1.4A
Camera5D Mk III5D Mark III
Sharpness1621
Transmission1.4TStop1.7TStop
Distortion0.4%0.1%
Vignetting-2.4EV-1.5EV
Chr Aberration20µm6µm

11
Lenses / Re: Sigma vs Zeiss vs Canon
« on: April 17, 2014, 12:42:49 PM »
Remember that many of Canon's older lenses (of which the 50/1.8 and 50/1.4 are members) were designed for use with film and to be used in an era where people didn't regularly zoom in to minute levels of detail and compare notes with others all over the world. At best, said lenses were used to create images that were blown up to A3 size prints.


12
Lenses / Re: Sigma vs Zeiss vs Canon
« on: April 16, 2014, 01:14:09 PM »
Would you like to address the comment I made about spherical aberration without referring to bokeh or polarisation?


Polarization was merely an analogy as an effect, like bokeh, that cannot be fully replicated in post-processing.  As for addressing your comment about spherical aberration without referring to bokeh, the point is that the residual spherical aberration designed into the 50L is there because the lens designers chose to emphasize bokeh quality over sharpness for the designof the lens.  If you're going to slam the 50L for not being as sharp as other 50mm lenses, the reasons behind that somewhat reduced sharpness are an integral part of that discussion. 


Acutally, I wonder if the Lytro camera would support the creation of S-A in software ... but that's not related to this.

Quote
Next up, let's discuss the interactions between planets…but we must avoid referring to gravity in that discussion.  ::)


If spherical aberration is so important and necessary to photographers then why do lens manufacturers go to such great lengths to eliminate it?


As has been established and accepted by many people (other than you), Canon intentionally chose to not eliminate spherical aberration from the 50L design.


Apart from Canon stating that the 50L was designed for portraits, etc, is there any actual evidence of Canon deliberately not eliminating spherical aberration?

btw, let me refer you to the wikipedia page here:
http://en.wikipedia.org/wiki/Spherical_aberration
what does it say about the top lens?
Is that the word perfect used to describe a lens without spherical aberration?

What would be really good is if someone could find the patent for the 50/1.2L and translate the Japanese to see what that says about the design, specifically if it states something like "this lens element mitigates (or reduces or ...) spherical aberration by ..." or if the patent says the reverse.

13
Lenses / Re: Sigma vs Zeiss vs Canon
« on: April 16, 2014, 01:03:22 PM »
My 35 Art´s AF is drifting again (a third AFMA with Focal showed a further 4 step adjustment, on top of the 7 steps I got between the one I did when I got it and Christmas), so I must admit I am a bit skeptical to that part of sigma. But since so many are happy with it, I hope my AF problem is a one-off.


I have a technical query here:

As far as I understand, the purpose of AFMA is not to 'fix' defective lenses, but calibrate a specified lens to a given camera to account for manufacturing tolerances.
Once the AFMA is done, the camera knows how much to compensate for this lens, and everything is hunky-dory.

But in what condition can AFMA drift as is happening in Eldar's case? Is it because something is moving within the lens and a gap is getting bigger or a cog is becoming more loose?

I am particularly interested since I just acquired a 35A (so far it looks like it is focusing right on target as shown below- spot focused on "6" using a peripheral point and center point respectively), I haven't run it through FoCal yet.

AFMA is purely a camera body firmware thing. It only reconfigures the body, it does nothing with the lens. Drift is a pretty odd thing, but I'd like to know more. Spherical aberration can result in the focal plane shifting when you stop down or open up. Since lenses usually focus wide open, then stop down for the shot, spherical aberration can result in your focal plane ending up in an unexpected place.

The Canon 50mm f/1.2 and Canon DSLR bodies include firmware that compensates for this. There is a known component of spherical aberration in that lens (by explicit design), so the focus shift caused by it can be mathematically compensated for. When you have your aperture setting tighter than f/1.2, the firmware will focus the lens with a compensation shift to ensure that once stopped down, the focal plane is where you want it to be.

If the Art 35 has some spherical aberration, it is highly unlikely that such a focus shift is compensated for. That would require paired firmware between the lens and body. Assuming that is actually the problem. If the focal plane is shifting at the same aperture, then that is a different problem, and likely due to the lens, rather than the body.

Hmm, an argument based on FUD - Fear, Uncertainty and Doubt.

Let me put this differently:
1) How many lenses do Canon provide spherical aberration correction for in camera firmware?
2) Do Canon DSLRs provide correction for spherical aberration in every Canon lens?
3) Do you think Canon want to have to correct for this in software?
4) Wouldn't it be easier to design lenses without spherical aberration and not need to correct for it anywhere?

14
Lenses / Re: Sigma vs Zeiss vs Canon
« on: April 16, 2014, 12:52:10 PM »
I'm pretty sure that you can introduce spherical aberration through plugins or other software components if you really so desire. What you can't do is correct for poor image quality at capture time.

Actually, spherical aberration is an effect in three dimensional space.

If spherical aberration is so important and necessary to photographers then why do lens manufacturers go to such great lengths to eliminate it?

Quote
Anyway, in the main the comments above about justifying Canon's current design and product are more about trying to ensure that people who worship Canon find a way to present Canon's offering as good and justified so that they feel good about owning Canon products. That's it. I'm sure someone will argue here that this comment is wrong, but you don't see anyone saying that they wish the 70-200/2.8 II had soft focus like the 50/1.2L and so on.

It has nothing to do with justifying or worshiping Canon. Your assuming something, then using your assumption to put words in peoples mouths as an attempt to win an argument. That's kind of you staple there, Dilbert. :P Why not try to put up a legitimate argument sometime, eh?

What exactly am I assuming?

Quote
It simply has to do with exposing people to opinions other than their own. There is more than one way to design a lens, and there are reasons for designing lenses differently.  I honestly do not think it would be good for every 50mm lens on the market to have exactly the same specs, offer the same exact IQ, produce the same aesthetic.

That's priceless.

Quote
It's better to have a diversity of options, because not everyone photographs the same things in the same ways that you do.

Of course. Nobody else is interested in lens that produce sharp images, have excellent colour rendition and contrast. Especially not a standard length zoom at 50mm.

If I recall correctly you like long telephoto lenses for birds, etc. Would you prefer a long lens that had the characteristics of the 50L or the Sigma 50/1.4 Art?

15
Lenses / Re: Sigma vs Zeiss vs Canon
« on: April 16, 2014, 10:13:47 AM »
I'm pretty sure that you can introduce spherical aberration through plugins or other software components if you really so desire. What you can't do is correct for poor image quality at capture time.

There are polarization effect filters for post-processing, but they cannot properly replicate the effects of having a CPL on your lens at capture.  Similarly, adding spherical aberration in post will not correct for poor bokeh in the captured image. 

I'll just point out that I didn't mention polarization or bokeh, so I'll take your dalliance off topic as an indication that I was on the money but you can't admit it

Wrong again (or perhaps that should be, wrong as usual).  Obviously, you don't comprehend the relationship between spherical aberration and bokeh, and the analogy of polarization failed to enlighten you.


Would you like to address the comment I made about spherical aberration without referring to bokeh or polarisation?

Quote
You're no more correct in this case then when you thought a lens was a camera, although I must say that was a particularly egregious example of your ability to totally miss the point.  Frankly, you have made dozens of similar, if less colossal, factual mistakes in this forum, and your credibility is basically nil.


Ok, so you're trending close to making personal attacks here, which is usually an indication of not having a sound argument of fact on a matter. Would you like to get back on topic or continue and get more personal with your remarks?

Quote
No. The problem that we're seeing here is something called "confirmation bias", where people find any reason at all to support the idea that the Canon 50/1.2L is better.

Again you miss the point.  Is anyone saying the 50/1.2L is sharper?  Not that I've seen.  If you want to define "better" as sharpest, that's a judgement by you. 

The problem that we're seeing here is something called "false-consensus effect," where people believe that everyone's definition of 'better' or 'best' is the same as their own, personal definition.


Interesting thought. I'll have to ponder that one. I suppose this makes room for accepting that whilst the 50L is acceptable for some photographic uses, there are clearly those where the Sigma 50 Art is going to be better and that since people generally own a lens for a specific purpose that those who already own the 50L probably aren't going to see any benefit from changing to the S50A, right?

Quote
False-consensus effect:
http://en.wikipedia.org/wiki/False-consensus_effect
"...a cognitive bias whereby a person tends to overestimate the extent to which their beliefs or opinions are typical of those of others."


hahahahaha

Following up one wikipedia reference with the use of another. You know they say that imitation is the most sincere form of flattery. Can I thank you now or later? :)

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