Karl Gnter Wnsch

Karl Gnter Wnsch

Lives in United States AK, United States
Works as a software developer
Joined on Jun 24, 2002

Comments

Total: 165, showing: 61 – 80
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On Canon EOS 7D Mark II First Impressions Review preview (2268 comments in total)
In reply to:

Lab D: First I read this and then I saw the new Samsung. I don't know anyone who buys Samsung, but it seems to beat the 7D in every spec.
For example 10 FPS is not exciting when others are offering 11,12 and 15 FPS. "Full HD" video is boring when other shoot 4K.
I just hope the 7D does use the same technology in this new sensor as found in the Rebel T2i.

Everybody will buy the Canon, nobody will get the Samsung. The latter simply doesn't have the lens system to back it up. It could have the holy grail of autofocus, without the lenses it's a DOA - and there are only lenses up to 200mm available (and it's a slow one)...

Direct link | Posted on Sep 15, 2014 at 12:54 UTC
On Canon EOS 7D Mark II First Impressions Review preview (2268 comments in total)

@DPreview, the remote connector type is not E3, it's N3!
And there are discrepancies in reported ISO ranges, either it's 50-12800 or 100-16000, depending on which page of your preview I choose to believe...

Direct link | Posted on Sep 15, 2014 at 12:26 UTC as 528th comment | 4 replies
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)
In reply to:

Karl Gnter Wnsch: If the "Sport" version is geared at the professionals which do not care that much about weight, why isn't it at least f/5.6? As f/6.3 they are missing the limit of the focusing systems - and since that is a physical limit the focusing on almost all DSLR will be compromized and not function as advertised and guaranteed by the manufacturers!

The new D750 is one (new) camera, how many more do have f/8 focusing capability?
"So it will work up to F8. Probably F11 with the center point. "
That's highly unlikely as f/8 already is very very tight and when a focusing module allows for f/8 focusing it also means that it's less precise for all apertures.

Direct link | Posted on Sep 12, 2014 at 14:37 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)
In reply to:

Karl Gnter Wnsch: If the "Sport" version is geared at the professionals which do not care that much about weight, why isn't it at least f/5.6? As f/6.3 they are missing the limit of the focusing systems - and since that is a physical limit the focusing on almost all DSLR will be compromized and not function as advertised and guaranteed by the manufacturers!

@D1N0, the -3 EV focusing has nothing to do with the aperture limit imposed by the beam splitter positioning. If the beam splitter is designed to work up to f/5.6 then at f/6.3 the focusing will be unreliable even if you try it in blazing sunshine.

Direct link | Posted on Sep 12, 2014 at 12:32 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)
In reply to:

Karl Gnter Wnsch: If the "Sport" version is geared at the professionals which do not care that much about weight, why isn't it at least f/5.6? As f/6.3 they are missing the limit of the focusing systems - and since that is a physical limit the focusing on almost all DSLR will be compromized and not function as advertised and guaranteed by the manufacturers!

@Plastek: No it doesn't depend on the amount of light. Autofocus works by separating certain light beams and these are blocked beyond f/5.6 or f/8 (depending on focusing module design, for most cameras it's f/5.6 - and for the rest of the cameras it's f/8 only for a very limited number of focusing points located in the very center of the frame) by the aperture.
So only light that has passed in close vicinity of the aperture will reach the focusing sensor and many of the photons making up that light have been affected by the inevitable diffraction and thus are no longer fit for the purpose of focusing. Our sun could go supernova and the focus would still be compromised and have reliability problems!

Direct link | Posted on Sep 12, 2014 at 10:22 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)
In reply to:

b534202: So the 2x TC will work with these?

@Plastek, no it won't. You will have a lens+TC combination that is f/11-f/13 wide open, that means that the combination is diffraction limited even then - focusing will not work at all, about the same chance to get that working as satan ice skating to work...

Direct link | Posted on Sep 12, 2014 at 08:13 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)
In reply to:

brelip: oh, and great job Sigma. Though i do wish the C is APSC only to save more weight...

Again they both have FF coverage as having smaller frame coverage does have not a single benefit for telephoto lenses!

Direct link | Posted on Sep 12, 2014 at 07:38 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)
In reply to:

b534202: So the 2x TC will work with these?

It will be mountable but there will be not a single DSLR that will be able to focus with that teleconverter in place...

Direct link | Posted on Sep 12, 2014 at 07:35 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)
In reply to:

brelip: oh, and great job Sigma. Though i do wish the C is APSC only to save more weight...

Those lenses are lighter because they use lighter housing materials, APS-C limited telephoto lenses do need additional internal baffling and would thus be heavier if they used the same housing and lens materials. You can not make any of the lens elements on the subject side of the aperture any smalle and the lens elements on the image side of the aperture aren't that big to begin with.

Direct link | Posted on Sep 12, 2014 at 06:02 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)
In reply to:

Karl Gnter Wnsch: If the "Sport" version is geared at the professionals which do not care that much about weight, why isn't it at least f/5.6? As f/6.3 they are missing the limit of the focusing systems - and since that is a physical limit the focusing on almost all DSLR will be compromized and not function as advertised and guaranteed by the manufacturers!

Yet the focusing is unreliable because the focusing modules have the design limit which can't be bypassed. No amount of in line trickery can avoid that, the light reaching the focusing module is heavily compromized by diffraction - if the beam splitters even can let it pass due to their design!

Direct link | Posted on Sep 12, 2014 at 05:58 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)
In reply to:

brelip: oh, and great job Sigma. Though i do wish the C is APSC only to save more weight...

In telephoto lenses you can not save any weight by restricting it to APS-C use!

Direct link | Posted on Sep 12, 2014 at 05:42 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)
In reply to:

Karl Gnter Wnsch: If the "Sport" version is geared at the professionals which do not care that much about weight, why isn't it at least f/5.6? As f/6.3 they are missing the limit of the focusing systems - and since that is a physical limit the focusing on almost all DSLR will be compromized and not function as advertised and guaranteed by the manufacturers!

Yes, it would have had to be 107mm diameter instead of the 95mm they got now - but f/6.3 make it even incompatible with the 1.4x teleconverter for the pro grade DSLR which can focus up to f/8 - because for those the autofocus cutoff is quite a bit more pronounced. So if they do produce one lens for the "pro's" then they have made a big blunder by missing that limit.

Direct link | Posted on Sep 12, 2014 at 05:40 UTC
On Sigma announces two 150-600mm F/5-6.3 DG OS HSM zooms article (136 comments in total)

If the "Sport" version is geared at the professionals which do not care that much about weight, why isn't it at least f/5.6? As f/6.3 they are missing the limit of the focusing systems - and since that is a physical limit the focusing on almost all DSLR will be compromized and not function as advertised and guaranteed by the manufacturers!

Direct link | Posted on Sep 12, 2014 at 05:23 UTC as 25th comment | 17 replies
On Travel tripods: 5 carbon fiber kits reviewed article (85 comments in total)

I bought a Feisol CB-40D head about 3 years ago. To call it "unrefined" would be flattering it considerably. It's a rough, uneven gripping grease filled metal pod.
Since I recently got a really good head from another company and thus don't need the CB-40D anymore, I took the head apart. It's a real mess inside, many manufacturing tolerances are simples greased away - and since the grease has changed properties over time and now is rather amber like in mine the head has changed in properties.
Where once you couldn't lock down the panorama plate now you practically can't unlock it anymore. It still holds insane weights at an angle but to start a panning movement requires strong and incalculable amount of force (book your place in a fitness studio and work out those biceps), while panning it will almost lock down on it's own.
And always bring a big forceps along on your travels, if you inadvertently turn the friction setting while the head is locked you will need them...

Direct link | Posted on Jul 28, 2014 at 11:04 UTC as 32nd comment
On Is it true? New service detects processed photos article (88 comments in total)

I only see some sense if you need to prove that something is shown as is - like if you are documenting a crime scene or insurance claim. Then this function could supplement something like the image data verification data which Canon DSLR can add to any photo taken...

Direct link | Posted on May 7, 2014 at 09:59 UTC as 34th comment
On Sony SLT-A77 II First Impressions Review preview (657 comments in total)
In reply to:

Bob Janes: That wider focus area will be much appreciated on an a99 MkII..

@Azurael,
it's the other way around, the basic design of the AF module is geared up for full frame cameras, the same modules in a APS-C just makes better use of the same area coverage - and it covers as much area as is physically possible if you don't want to restrain the lens speed to be better than f/4 or even f/2.8 for the AF to work at all... So if you want to have lenses with a best aperture of f/5.6 to be able to use AF then you will have to live with that kind of area covery you got today...

Direct link | Posted on May 1, 2014 at 23:08 UTC

Yeah, so A-mount is still alive... not! They could have easily made that lens work on A-mount as well with matching/dedicated adapter for E-mount (a telephoto lens has no need whatsoever for a short registration distance, it brings no technical benefits) but no, they had to make it E-mount. So Alpha-DSLR/DSLT users brace, your system is on the chopping block...

Direct link | Posted on Feb 12, 2014 at 13:29 UTC as 3rd comment
In reply to:

samfan: When I was picking my DSLR brand in 2006, I chose Nikon over Canon. One of the reason was that Nikons always perfectly worked with 3rd party lenses, unlike Canon which used to have constant focusing problems with Sigma lenses.

And for years I've been using 3rd party lenses without problem, happy with picking Nikon.

Today? Screw Nikon. Most my favorite lenses are Sigmas. Honestly I'll rather switch to the Sigma SD1 than buy another Nikon DSLR and not be able to use lenses such as 50-150/2.8, 30/1.4 or 8-16mm. Especially since Nikon completely dumps on DX users and doesn't provide any alternative to these.

I also bought a V1 since there's nothing else like it but it's gonna be a cold day in hell when I buy a FT1 only for overpriced Nikon lenses.

Well you chose the system for all the wrong reasons... It wasn't Canon who did something wrong, it was Sigmas fault back then and it again is Sigmas fault today because they chose not to license the respective specifications but rather reverse engineer them, which is going to be prone to omissions due to as of yet unused but well specified features within the internal standard of cameras and lenses of the OEM...

Direct link | Posted on Nov 20, 2013 at 15:10 UTC
On Tamron to develop 150-600mm F5-6.3 ultra-telephoto zoom article (193 comments in total)
In reply to:

Hadarmil: Frankly, I'd give up some mm on both ends if they could make a faster super tele zoom. Oh, and keep it for crop sensors. We still don't have fast super telezooms for crop which would probably make them cheaper and lighter.
Maybe Sigma will understand the market hole(as they occasionally do) and act to fill it. Right now I doubt the Tamron will be as good and cost effective to become a serious success for serious photogs. feels more in line like the old tactics of shoving larger unusable focal lengths to catch press attention. 200-500 f/4 sounds a little better even if you can't upgrade with it to FF.

Heck, why doesn't anyone make a crop fast prime? A sharp 2.8 300 for crop will get my money and probably a lot of others'.

Rant rant rant. Sure do hope I'm wrong.

At the long end the lens speed dominates the size of the lens - from about 100mm onwards the image circle is so big that it can more than cover a full frame sensor. For a smaller sensor you would need to add additional internal baffling to reduce stray light entering the mirror chamber of the camera.
Telephoto lenses neither get cheaper nor do they get lighter for crop sensors!

Direct link | Posted on Nov 8, 2013 at 10:13 UTC
On Tamron to develop 150-600mm F5-6.3 ultra-telephoto zoom article (193 comments in total)

Why not make it f/5.6 at the long end, then at least all focusing systems would be within their working range! At f/6.3 nobody should buy this lens as it will not focus reliably on all but the top of the line DSLR...

Direct link | Posted on Nov 8, 2013 at 10:10 UTC as 21st comment | 5 replies
Total: 165, showing: 61 – 80
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