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Messages - Grummbeerbauer

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1
It will also be interesting how this lens performs compared to the 120-300 2.8 OS S with 2x TC (in particular the new 2x that were also announced by Sigma) ... that combo is said to be good, but not stellar, and will definitely cost more. But you do gain an excellent fast zoom in the process. Could still be a viable alternative for those folks that need 600mm only occasionally.

2
After the Tamron 150-600 turned out a bit disappointing for APS-C users on the all-relevant long end, I was really hoping for Sigma to deliver a product in that FL range - and they did not deliver one, but two! ;D

Since all their recent lenses have been stellar, I am really eager to see the first reviews.

Its a really interesting move to release two lenses with same FL and aperture range at once. Perhaps when their lens designers explored alternative designs for a 150-600 f5-6.3 they came out with two interesting ones, one more pricey to manufacture, but perhaps with better IQ or some other benefits.
And instead of picking the lesser design to win over Canon by price or pick the more advanced design to repeat what they did with their 35A, 50A, and 18-35A (which I have and love), they just decided to do both. Thumbs up for that gutsy call! 8)


3
Is it just me, or do the weight and filter size specs not sound a bit over the top compared to the Tamron with the same maximum aperture and focal length range?
Or is Sigma doing what they did with their 50mm Art, i.e., sacrificing weight and size (and therefore also cost) to get a boost in IQ that would not be possible with a lighter design?
In IT, we call this KIWI (kill it with iron).  :)

Nonetheless, this announcement is exactly what I had been hoping for after the Tamron turned out to be a bit of a let-down for APS-C users in particular on the long end.
If Sigma can deliver the same level of quality of all their recent Sports and Art lenses with this lens as well, and if the price stays well south of 2k€, I might be interested.

4
Wow!  Really F6.3 being marketed as a sports lens?  Maybe on the planet Venus.  Rarely is F6.3 enough to stop sports action.

If you're that close to the sun, an f16 lens will do.

Only if your sport is done in Venus orbit or in some fancy floating city high in the Venus atmosphere. Actually, the surface light level on Venus is very low:

"The cloud cover is such that very little sunlight can penetrate down to the surface, and the light level is only around 5,000–10,000 lux with a visibility of three kilometres. At this level little to no solar energy could conceivably be collected by a probe. Humidity at this level is less than 0.1%.[36] In fact, due to the thick, highly reflective cloud cover the total solar energy received by the planet is less than that of the Earth."

(from http://en.wikipedia.org/wiki/Atmosphere_of_Venus)

SCNR  :)

5
Third Party Manufacturers / Re: A Summary of Sigma Lens Rumors
« on: July 09, 2014, 01:03:36 AM »
I am looking for some halfway affordable longer zoom for occasional birding/wildlife/airshow shooting. The Tamron 150-600 almost had me convinced, but at least on APS-C the long end seems to be bad enough that one should probably use it as an 150-500. That puts me off and the fact that it is on backorder everywhere in .de.  ::)
If Sigma had something in that range (200-600mm?) with better IQ at the long end than the Tamron while keeping the price at a reasonable level (<2000), I might be tempted. I wouldn't even mind f6.3 at the long end if wide-open performance was acceptable.

6
To be honest, I have been considering buying more 3rd party lenses for my Canon bodies recently as Sigma seem to be knocking out some quality glass and their 35mm makes me very happy every time I use it. Looks like Canon are making that decision much easier for me with this news.

According to Wikipedia (read it elsewhere, too, just don't remember where), Sigma's entire production is still happening in Japan in their Aizu plant.
It is good to see that there are still companies that do not put maximizing profit over everything else and therefore do NOT shift production to those places on this planet with the lowest wages, the lowest standards of environmental protection, and/or a questionable human rights situation.

7
Third Party Manufacturers / Re: Tamron to Announce New Tele Zoom Next Week.
« on: November 02, 2013, 04:35:14 AM »
I don't know... I don't really find the "ancient IS" that much of a problem... Guess it depends what you're shooting with it but most of us are shooting wildlife and/or outdoor sports with it.  I've also found the "awkward push-pull zoom" to not be that awkward at all.  In fact when tracking a BIF coming in toward you, it's actually quite natural to slowly draw the barrel back toward you...

There is a reason that this lens is still relevant after all these years without an upgrade.  Here's a few from the old 100-400mm with the "ancient IS" turned on...

At it's price range, I don't think it's a bad option, especially for a "hobbyist"...  ::)  But that's just me!   ;)

I do not doubt that (a good copy of) a 100-400 in capable hands can deliver, and your shots prove that.
Still, I tried this lens a few times and cannot overlook the problems (some of them subjective, like push-pull zoom, others measurable like the IS). Add in that a replacement has been "just around the corner" for about five years now ;). This makes me somewhat hesitant to pay that price for something that might address many of the issues I have with this lens.


My dislike of the 100-400 is not

8
My longest lens is currently a 70-200 F4L IS and I am shopping for something longer for quite some time now.
I don't like the Canon 100-400 with its ancient IS and awkward push-pull zoom design, and optics could be better, too. A successor (if it ever comes into being) will likely cost 2,5k€ and is therefore most likely out of the question for a hobbyist.
The Sigma 120-300 2.8 OS has pretty good optics but is not as long as I would like it to be, heavy as hell and quite pricey, too.
The various Sigron 50/120/150/200-400/500 f4-f6.3 with and without OS/VC also do not cut it optically.
So lets hope Tamron delivers on this one.

9
Lenses / Re: Frontfocusing Sigma 18-35 1.8 on 7D
« on: August 27, 2013, 06:27:30 PM »
To finish the story of my copy of the 18-35: I asked a colleague (semi-pro photographer with lots of experience, not a pixel-peeping gearhead ;) ) to bring his backup 60D for testing. We tried it on both bodies in the same light on different targets at different subject distances and this basically confirmed what I observed on my 7D and on my 450D: At 35mm it is OK at close subject distances, way of at longer subject distances, and off by a mile at 18mm.

BTW: He had his Canon 50 1.4 on the 60D instead of a lens cap, so I tried it on my 7D: Focus was spot on. So it is definitely not an iffy AF on my 7D body.

Since I am not willing to bet on being able to fix these issues with the Sigma dock & software (and spending several hours of my precious free time in the process), the lens is going back to Amazon tomorrow. Since I am not yet willing to totally give up on this lens model, I asked for a replacement. Maybe I have better luck this time.

10
Lenses / Re: Frontfocusing Sigma 18-35 1.8 on 7D
« on: August 27, 2013, 06:16:26 PM »
The width of the confirmation range has no correlation to the accuracy of the VF confirmation since it's the midpoint of that range which is used for DotTune. The width of the range is intentionally padded by camera firmware to make it easier for those who rely on the VF confirmation for manual focusing - a narrower range would make it difficult if not impossible to quickly MF, particularly on lenses with short focus ring throws. Firmware applies padding in equal amounts to both sides of the tightest point of phase detection, thus the midpoint of that range is the apex of focus. On Canon bodies the amount of padding is the same for both AF and MF modes; on Nikon bodies the firmware pads the range by 2x when in MF to further assist those acquiring focus to the dot, which is why the video tells Nikon users to keep the lens in AF mode to assure that the confirmed range fits within the +/- 20 AF tuning range.

Interesting info, thanks for that.
It would be great if one could choose less padding for MF in some custom setting.
While I am spelling out wishes: It would be great if all lenses offered adjustment options like the new Sigma lenses and if it could be done on camera (maybe via USB connection to have the better UI of a desktop application).

And it would be even better if we could just set up camera and test target, type in the measures subject distance, and have the software trigger test shots (one done with CDAF for comparison), adjust AF settings in between, and figure out the optimal AF adjustment settings all by itself.  8)

Of course this can only be done by a camera system manufacturer, not for third party lenses... well, unless Sigma gets in contact with the MagicLantern guys to add their own Sigma auto-AF adjust plugin. If ML can more or less directly access the EF mount contacts to implement Sigma's protocol for doch-2-lens communication in software.


11
Lenses / Re: Frontfocusing Sigma 18-35 1.8 on 7D
« on: August 25, 2013, 05:05:38 PM »
I have the same problem with mine on the 7D and Rebel XT.

Oddly, it's fine on the 5D Mark III.

I presume that with "same problem" you are referring to the general need for different AF adjustments settings?

Interestingly, Roger Cicala at lensrentals.com had a four-part series of articles on autofocus precision, starting with http://www.lensrentals.com/blog/2012/07/autofocus-reality-part-1-center-point-single-shot-accuracy (links to the subsequent articles are at the bottom). Very interesting read in general. In articles 3a and 3b he also found out that newer Canon bodies (from 5DIII onward) if combined with newer lenses focus considerably more accurately than older bodies (including the 7D).
That sort of confirms my own experience:I have never been too satisfied with the AF precision of my 7d anyway, it has always been hit and miss (could of course also be my technique, but what technique can be messed up when setting up the camera on a tripod and point it at a non-moving high contrast target?).

I think I will have to do some shots at daylight this week to see if the type of lighting also plays a role. Although a prime lens like this is of little use if it doesn't AF well in low or artificial resp. mixed light.

12
Lenses / Re: Frontfocusing Sigma 18-35 1.8 on 7D
« on: August 25, 2013, 04:52:23 PM »
In particular, contrast detect AF on the 7D has been shown to lack precision, so as the basis got 'dot tune' I wouldn't rely on it.

Contrast detect AF is not the basis of DotTune. As described in the video, either CDAF or manual focusing can be used, whichever method the photographer finds more convenient and/or accurate.

I used CDAF for initial focus and did some manual fine tuning. In any case, the precision was excellent.

13
Lenses / Re: Frontfocusing Sigma 18-35 1.8 on 7D
« on: August 25, 2013, 04:50:45 PM »
I don't fully believe the 'dot tune' method, I'd recommend FoCal or at least commercial tool like LensAlign.  In particular, contrast detect AF on the 7D has been shown to lack precision, so as the basis got 'dot tune' I wouldn't rely on it.

I am also not fully convinced of the dot tune method... after all, in my case I had a range 20 (from -3 to +16) in which I got a stable focus confirmation... that is half of the AF adjustment range! And that was at 35mm and f1.8, i.e., the narrowest possible DoF with that lens.

Regardless, it's certainly possible for a lens to require a different AFMA at the MFD vs. a reasonable distance away (although 20 units is a big difference!).  Then again, AF issues are Sigma's Achilles' heel. However, you might consider the Sigma Dock (which I'd assume is compatible with this lens, but I haven't checked). 

I am indeed about two clicks away from ordering the USB dock, because I would really want this lens to work for me. Seems that for this lens, the Sigma software allows adjustments at 18, 24, 28 and 35mm and for subject distances of 0.28m, 0.35m, 0.5m and infinity, see the screenshot in the DPReview here http://www.dpreview.com/articles/4406844237/sigma-usb-dock-quick-review/2.

14
Lenses / Frontfocusing Sigma 18-35 1.8 on 7D
« on: August 25, 2013, 01:30:01 PM »
Hi all,

I currently have an EOS 7D with a number of lenses, mainly Canon mid-range stuff (24-105L IS, 70-200L F4 IS, 17-55 2.8 IS, 100L 2.8 IS Macro, 85 1.8 ) and two Sigmas (30 1.4 EX (i.e., the old one), and the 10-20 3.5-5.6 EX).
I had always wanted a short FL prime lens which ended me up with the Sigma 30 1.4, but its lousy AF (both regarding precision and consistency) and soft images below f2.0 make me use it only on rare occasions where I can live with a low number of keepers.

I had been eying the new 18-35 1.8 since it was announced, even more so when the first rave reviews came in. Prime like quality and aperture in a zoom, simply amazing. Getting what basically seems to be a "variable FL prime lens" ;) I pulled the trigger when there was a good deal on Amazon recently (710€).

When it arrived, I was thrilled by the lens' haptics and feeling for quality, which is better than any of the Canon L lenses I own and just light years away from the Sigma 30 1.4 EX with its delicate "crinkle" finish and scratchy AF ring.

Focal-length-wise, while the 18-35 is definitely not an "always on lens", I found it to be very useful for a variety of situations.

I had no intentions to shoot any test charts, so I started testing it mainly indoors in mixed light with mainly static real-life subjects, which is my primary use case for such a lens. To my great disappointment, this particular copy on my particular body appears to exhibit a considerable frontfocus. So I printed an autofocus test chart (the one found at http://www.klein-bild.de/focus.htm ) and did some test shots at 35mm and varying subject distances. I always set focus back to MFD or infinity before autofocusing again and did three test shots at each distance and AF adjustment setting. For each subject distance, I concluded the series with a shot focused manually with live view for comparison. 
The good news is that different from my 30 1.4 EX, autofocus was very consistent. But that's where the good news ended already.

It turned out that both at around 1 meter and at 0.5 meter subject distance, I needed to dial in a whooping +20 to get about the same level of sharpness that I got from MF (see screenshots below, the legend is in German, "Motivabstand" meaning "subject distance"). While I would not like the idea of having to do such a huge adjustment, I guess I could live with that.
However, at 0.35 meter subject distance, I got the best results at an adjustment setting somewhere between 0 to 10. That meant that at the +20 setting that I would need for the longer subject distances, I would be in the "barely acceptable" range of sharpness. Anyway, at that point it became pretty clear that even for a single  focal length, the single adjustment value my body offers me would not suffice.
Being tired of test shots for the moment, I then did some additional research and found the "dot tune" focus adjustment method (check out this video: DotTune: Autofocus fine tuning in under 5 minutes ), which seemed to make a lot of sense and promises much faster adjustments and does not require taking hundreds of test shots.
I tried it out at 35mm and 1,75m subject distance (as recommended for dot tune, 50 times FL). I found the range where I got a stable focus confirm to be between -3 and +16, which would indicate a correction setting of +6 or +7.
The big surprise was at 18mm and 0,9m subject, the range of stable focus confirmation only started (!) at a correction value of +17.
I could visually confirm both correction values with actual test shots.
A quick test on my trusty 450D basically confirmed the results on the 7D: Considerable front focus at 35mm which gets better at shorter subject distance, and a plain massive front focus at 18mm.

tl;dr

I found that the Sigma's AF is consistent at a certain focal length and subject distance, but would require different correction values for different FL/SD combinations. This gives me some hope that I could fix it with the Sigma USB Dock and some patience, but I am just not sure if I am willing to accept this.

So what should I do?
Keep it and get the USB dock? I have a week before my "no questions asked" return period expires.
Or send it back for good?
Any comments or similar experiences welcome.

Regards

Grummbeerbauer


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EOS-M / Re: Some EOS M Information [CR1]
« on: August 20, 2013, 10:46:50 AM »
I think if Canon put the 70D sensor into the next EOS M camera (a quite obvious move, wouldn't it?) that could quickly turn the M system from the being the EVIL system with the worst AF speed (although the recent firmware upgrade seems to have mitigated that issue at least to some degree...) to becoming market leader - in particular for tracking moving objects, where a purely contrast-detection based AF system has a serious conceptual disadvantage.
If they get this to market, I might seriously consider adding an EOS M2 (or whatever the call it) as a backup body to my 7D.

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