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DonSchap
01-18-2008, 01:27 PM
Well, the day has finally come ... and one I never really thought would.

I'm actually buying a SIGMA brand lens that I want. LOL :rolleyes:

Yeah, add it to the gearhead's list: SIGMA 10-20mm f/4-5.6 EX DC (SONY mount)


32561


Now, I thought I would have no problem with waiting on buying this lens ... as the local store had three of these SONY-compatibles, last week, at Calumet Photography, in Oak Brook. Today ... Zero! What the heck? :confused:

I made mention of how this was the preferred lens in Great Britain and wham ... sold out. Next time ... I'm waiting until I have mine, first, before I say anything like that again. :cool: Even the guy on the phone was going on about how much he liked this particular lens. Admittedly, the construction seemed a bit more thought out, for this lens. Less light bending in the first few elements. That's gotta result in less distortion and sharper imaging.


SIGMA 10-20mm
32565




TAMRON 11-18mm
32564


So, okay ... my SIGMA-cherry is gone! :eek: Both the SONY 11-18mm and the TAMRON 11-18mm are inferior in comparison (they're the same lens - shhh, don't tell anyone), plus they're both more expensive, too. Guess you are paying for that "extra" element. (A nod to "Coldrain") The apparent quality of output is not especially reflected in the price.

Yes, I'm giving up the TAMRON 6-year warranty for a better shot. Oh, the trade-offs I make. I'm so ashamed ... :rolleyes:

SONYNUT
01-18-2008, 09:03 PM
pretty dark lens

DonSchap
01-18-2008, 09:26 PM
This is a pretty "standard" base aperture for most wide-angle zooms.

The TAMRON 11-18mm is f/4.5-5.6
The Canon 10-22mm is f/3.5-4.5
The SIGMA 12-24mm is f/4
The Tokina 12-24mm is f/4
The Nikon 12-24mm is f/4 ...
there is a bright side ...
The Nikon 14-24 f/2.8 <- a rare find.

Anyway ... here's to the dark side ... which is a good segway to ...

my intent, which is to start taking "architectural shots" of local homes for the upcoming realty/government farce when everyone gets tossed to the curb for not paying on their enormous mortgages. It's weird, no matter how many times I think about this, I realize that the government really allowed this happen to just raise property taxes with all these super-high mortgages. Then ... the bottom fell out. :eek:

Anyway ... all these houses are for up sale and they need to be photographed. Like they say, a time and place for everything ... even opportunistic photography. Beats being a paparazzi I suppose. The subjects don't run off, get drunk or drive over people. :rolleyes:

DonSchap
01-22-2008, 02:59 PM
Okay ... the SIGMA AF 10-20mm f/4-5.6 EX DC came, today. I unboxed that bad boy and fired up the ol' α700, to give it a shot.

Okay, at 10mm ... f/4 isn't going to be an option for sharp focus, close up. It's rather fuzzy. Even with flash ... nothing sharp, Repeated focus ... no improvement. It looks as though going to f/8 may have to do for the bulk of the heavylifting. I sort of expected this level of performance, but I had hoped. :rolleyes: 10mm does offer one hell of a view, though, as you might expect. Almost wall to wall, so to speak.

The weather, here, is getting way too slippery to chance running around with it, in the near future. I'll do some other focusing tests, later tonight .... but as lenses go, this remains to be seen ... (don't they all?) :cool:

Rooz
01-22-2008, 06:40 PM
hmm, i gotta disagree with you here Don. even wide open at 10mm the sigma is still pretty sharp in the center. the borders sharpness and distortions are where the issues lie.

DonSchap
01-22-2008, 08:02 PM
Well ... I did some comparisons, using a tripod, against the TAMRON SP AF 17-50mm f/2.8
and I wasn't thrilled by the SIGMA 10-20mm f/4-5.6 in the comparison.

I set both lenses to 17mm (lens barrel indicated) @ f/5.6, which is the best the SIGMA can do at this focal length. I simply swapped the lenses ... and multifocused for the best shot.

I place the 100% crops side-by-side to compare them.

Here are the results:

SIGMA 10-20mm @ 17mm f/5.6 original image
32694

SIGMA 10-20 100% crop
32693
SIGMA ^

TAMRON V
32692
TAMRON 17-50 100% crop

32695
TAMRON 17-50mm @ 17mm f/5.6 original image


Then I set the new SIGMA lens for 10mm ... at the same f/5.6 exposure ... just to be fair.
32696

Then upped it f/8
32697

Then finally f/11
32698

I'm sorry, but 10mm is significantly softer at f/5.6. I'm shooting at the minimum focal length ... which is neither here nor there ... but demonstrates the truly nice close-up cabilities of these two lenses. Unfortunately, you have to crank down on the aperture, at 10mm, to sharpen your focus to a reasonable level with the SIGMA.

Is it me, or does the TAMRON seem a little better at color, also?

I'll look at distortion, later.

Rooz
01-22-2008, 08:12 PM
oh come on. you have to compare like for like. the 17-50 tammie is an exceptionally sharp f2.8 lens. chalk and cheese Don.

DonSchap
01-22-2008, 08:21 PM
Rooz ... you use what you have handy. I suppose I could toss it up against the "freebie" SONY DT 18-70mm f/3.5-5.6 kit lens ... but a $500 lens against a ... freebie? That's fair?

The TAMRON AF 18-250mm f/3.5-6.3 XR Di-II LD wouldn't put up much of a fight because it is just too much of a compromise in focal length. It was built for convenience, not sharpness end-to-end. I kind of expect that out of these shorter-distance focal lengths, though.

The 17-50mm was designed exceptionally well, there is no doubt. It is a staple for many photographers. Personally, I do not plan on having two UWA lenses in my bag. Shooting it against another will be kind of rough. I've already conceded that it probably shoots better than the TAMRON SP AF 11-18mm f/4.5-5.6 Di-II LD, by design alone. That's kind of why I broke down and bought the SIGMA AF 10-20mm f/4-5.6 DC EX in the first place.

Honestly, I wish I really could use my TAMRON SP AF 11-18mm f/4.5-5.6 Di-II LD for a comparison shoot, but I have nothing to hang it off of these days. I sold the only body I had that it could ride on to a fellow DCRPer. It's, unfortunately, a Canon-mount. I can't even use it on my Canon EOS-3 35mm-film camera body ... because of it being a Di-II design only for APS-C sensors.

But, be that as it may, even you can see the focus softening from the 17mm-shot to the 10mm-shot, and that's really where my complaint lies, if any. I'll have to use the tighter aperture (f/8 or f/11) to make up the difference. I hoped I had successfully pointed that out. Guess not, huh? :confused:

Rooz
01-22-2008, 08:37 PM
like for like is referring as much to the type of lens rather than the cost. you can compare a #300 sigma 50mm macro lens and then be devastated at how sharp it is compared to more expensive glass. the sigma is a wide angle lens. i think if you compare the res figures of "like lens'" it stacks up pretty well. (although if i had my time again i'd buy the tokina).

i appreciate what you're saying and what you're indicating in your test, my point i guess is perhaps you need to learn how to use it and for what purpose. here you go...this guy seems to have the hang of it. be warned its used on just a piece of shit d40 though. :p

http://www.flickr.com/photos/markgibson/

DonSchap
01-22-2008, 08:49 PM
He's shooting at f/16, for goodness sake.

And "SONYNUT" was worried about being too dark.

Oh, I give up! :p

Anyway ... one last comparison, later tonight (1/23), ... the stout Tokina AF 20-35mm f/3.5-4.5 against the SIGMA AF 10-20mm f/4-5.6 DC EX @, of course, 20mm @ f/5.6 <= right where they meet!

Just so the complaining is hedged ... LOL. My Tokina is over 10-years-old, so it should be a real battle ... on the order of GrandDad against GrandSon. :eek: "Hey s-s-sonny, be there!"

DonSchap
01-23-2008, 07:58 PM
Okay ... 20mm showdown at 1-foot (minimum focusing distance for the Tokina AF 20-35mm f/3.5-4.5)

Okay ... all lenses set to an indicated 20mm, aperture set to f/5.6 and the lens swapped on a tripod mounted α700. Each lens was autofocused, several times, to remove any doubt.

Ready ... GO!

Tokina 20-35mm (age before beauty) 100% crop
32732

SIGMA 10-20mm (our competing entry) 100% crop
32733

TAMRON 17-50mm (staunch performer) 100% crop
32734


Well, it's pretty clear that at 20mm, the SIGMA slightly outperformed the Tokina ... the image just looks better, clearer. The TAMRON ... as you can see ... just ran away with it. <Shrug> I know what I'm using for a 20mm shot. :rolleyes: That contest is a no-brainer.

I guess, to be honest, I expected just a little better performance out of the SIGMA, especially at the "far end." I mean, this was the Tokina's "widest-end", so what can you expect? TACK SHARP ... it ain't.

Whatever! :rolleyes:

Still have yet to do distortion. Now, where are those goal posts?

DonSchap
01-24-2008, 05:00 PM
Since I got the Whale Tail, I've wondered how it might work out with a 10mm-shot of a room. Well ... after trying it out ... Buzz! Not what I'd like. I then tried the direct flash idea, straight across to the subject ... Buzz ... rediculously directive.

Okay ... the famed "ceiling bounce", on bended knee ... no diffuser over flash.
32748
Buzz ... not enough light, dark edges.

Okay ... the little plastic flap diffuser extended over the flash lens ...
32747
Ding-Ding-Ding ... Folks, we have a winnah!

Yeah ... that little diffuser darn near lit the room, using the lens' 10mm focal length. When you just want to light a room with a low ceiling, with no one in it, and all you have is your portable external flash ... this is how. :cool: When you add people ... well, then that's something else.

DonSchap
01-25-2008, 11:29 AM
Well, I knew I was going to regret going this SIGMA route and ... damn it, here we go, again! :rolleyes: Remember: you have to pay shipping to send it back ... there goes another $30! :mad: I might as well just keep FedEx™ on the payroll.

AM I being unreasonable? All I ask for is a lens I can pull from the box, place on my camera and it works ... as designed! If we are going to be expected to return the damn things, you can at least throw in a "return mailer" and cover the shipping. Cripes, this is no bargain! It's a SHAME!

Sigma Corporation of America
15 Fleetwood Ct.
Ronkonkoma, NY 11779

Attn: Service Department

Dear SIGMA Repair:

I was going to exchange my brand new SIGMA 10-20 f/4-5.6 DC EX (SONY-mount) lens with the retailer I bought it from, but they are currently out-of-stock, locally, and it is on backorder with no determined date of restock.

Therefore, I am submitting this new lens to your facility for adjustment & calibration due to severe softening at 10mm, 17mm and 20mm settings.

I have included several prints of the comparisons and what my SONY α700 camera is capable of with other lenses mounted. These measurements were taken at approximately 8 to 12 inches away from the subject, depending on the setting of the focal length and Minimum Focus Dist. of the comparison lens. I was informed that this lens is capable of a much higher-degree of sharpness, at these settings and I am concerned enough to have you take time out to examine and correct it, as much as possible.

I would appreciate a timely turn-around (7-10 days) of what your Customer Service people are saying is becoming a rather "routine event" with your new lenses.

Also, I would appreciate a detailed explanation of exactly why I should consider future SIGMA lens purchases for my camera, in light of this apparent "quality control issue" and "out-of-the-box" failures.


Sincerely,
Don Schap
Certified Photographer

VTEC_EATER
01-26-2008, 08:54 PM
I wouldn't say you are being unreasonable. I considered your example photos to be unacceptable in my book.

I had a tough decision some months back when I was in the market for an ultra-wide. I tried the Sigma 12-24 against the Nikon, and it was clear as day that the Nikon was sharper in all respects. I would have thought the Sigma would have been competitive against the Nikon considering it is designed for full frame and I was using the "sweet-spot" of the lens. The test shots showed that the Sigma just sucked. Maybe it was a bad copy, or maybe it was just a fact that the Nikkor is a much better lens.

I never got to try the 10-20 as Helix did not have one in stock, but my mind was made up after using the Nikkor. I threw down my $1000 after tax and walked out the door never regretting my decision.

The Nikkor still amazes me every time I shoot with it. Its very sharp between F/8 and F/11, and still produces fantastic results at larger apertures.

Hopefully your calibrated 10-20 comes back working much better. If not, I would possibly hold out for a Tokina release. The Tamron just does nothing for me. I tried one out at a store about a year ago, and it was rather blah to me. Nothing really stood out and made me go "wow."

DonSchap
02-23-2008, 07:17 PM
TAMRON has announced their intention to build and release a 10-24mm UWA.

Here's the news!

TAMRON DEVELOPS SP AF10-24MM F/3.5-4.5 DI II LD ASPHERICAL (IF) (MODEL AB001)



A New High Performance Zoom Lens Designed for Exclusive Use on Digital SLR Cameras Covering the Ultra Wide-Angle Range



PMA, January 31, 2008, Las Vegas, NV— Mr. Morio Ono, President of Tamron Co., Ltd., announced the development of the SP AF10-24mm F/3.5-4.5 Di II LD Aspherical (IF) (Model AB001), a new high performance ultra wide-angle zoom lens designed exclusively for digital SLR cameras with APS-C size imagers.
* “Di (Digitally-Integrated design)-II” lenses are designed for exclusive use on digital cameras with smaller-size imagers.
* This lens is not designed for use with 35mm film cameras and digital SLR cameras with image sensors larger than 24mm x 16mm.

The new SP AF10-24mm F/3.5-4.5 Di II LD Aspherical (IF) is an advanced ultra wide-angle zoom lens that is versatile and offers even higher performance and specifications than the current Tamron SP AF11-18mm F/4.5-5.6 zoom lens.

The lens covers an extended focal length range that is particularly wide for an ultra wide-angle zoom lens, while improving the aperture to F/3.5-4.5 and keeping the filter diameter to 77mm. Its lightweight and compact size makes this new wide-angle zoom very user friendly.

The lens was designed for use with digital SLR cameras and thereby employs special optical glass materials for outstanding optical performance such as large-aperture glass-molded aspherical elements and hybrid aspherical elements.


Main Features

Compact Ultra Wide-angle Zoom Lens Covering a Broad Range from 10mm to 24mm
The new Tamron zoom covers a focal length range equivalent to 16-37mm* when converted to a 35mm full-size format. Its ultra-wide zoom ratio of more than 2X provides a versatile variety of angles of view, thus improving photographic creativity.
*Tamron’s conversion ratio is 1.5x.

Features an Optical Design Optimized for Digital Camera Characteristics Ensures High Optical Performance
(1) Employment of Special Optical Glass Materials Provides High Performance The new zoom lens uses an HID glass element and a pair of LD glass elements to minimize on-axis and lateral chromatic aberrations that are the greatest hindrance to high optical quality. To further achieve outstanding optical quality, the lens uses a high quality, glass-molded aspherical element and three hybrid aspherical elements to thoroughly compensate for spherical and comatic aberrations and distortion.
* HID – High Index/High Dispersion optical glass
* LD – Low Dispersion optical glass

(2) Optical Design Optimizes the Angles of Incidences of Light Rays Reaching the Imager The ultra wide zoom lens uses a new optical system designed to confine the changing angles of incidences of light rays reaching the imager within a certain scope over the entire image field from the center to the periphery, by considering the effects of variances due to zooming.

(3) Enhanced Peripheral Illumination Peripheral light fall-off is minimized so that images are high quality from the center to the periphery.

(4) Outstanding Resolution As an SP Di II class lens, it provides high optical quality in terms of resolution, contrast and flatness of image field.

(5) Internal Surface Coating Reduces Ghosting and Flare The lens uses a newly developed multiple coating and internal surface coating, (i.e., multiple-layer coatings on cemented surfaces of plural lenses) to reduce the image degradation caused by the reflection of light rays entering from the lens front and affected by the imager.

Ultra Compact and Lightweight Design
The new zoom lens covers a wider focal length range with a greater zoom ratio and offers a faster maximum aperture and enhanced optical quality than the existing SP AF11-18mm zoom lens. Despite higher specifications that are likely to incur a bulky design, the new zoom lens is lightweight and compact. Tamron has successfully realized a versatile ultra wide-angle zoom lens that is lightweight and compact enough in overall length and diameter to accept a 77mm filter, the same as the existing SP AF11-18mm zoom lens.

Minimum Focus Distance of 0.24m throughout the Entire Zoom Range
Considering the importance of “close focusing capability” as an essential condition in wide-angle photography, Tamron has achieved a 0.24m minimum focus distance over the entire zoom range. Getting closer to the subject allows you to easily express a more creative photographic vision.

Flower-shaped Lens Hood
A glare-reducing flower-shaped lens hood is included as a standard accessory. The special hood provides optimum shading of superfluous light rays that enter from the rectangular frame outside the image field.

New External Design Conveying “High Performance, High Precision Image” on the Basis of Tamron’s Conventional Lens Design
The external design is improved to enhance the uniformity and smoothness. The metallic finish of the gold band of Tamron lenses makes it stand out as a Di II lens, while the layout of alphanumerical markings is improved for better visibility. The rubber patterns of the zoom and focus rings have also been improved to compliment today’s digital camera design style and to provide better handling.



Specifications
Tamron SP AF10-24mm F/3.5-4.5 Di-II LD Aspherical [IF]
Model Name AB001
Focal Length 10-24mm
Maximum Aperture F/3.5-4.5
Minimum Aperture F/22
Angle Of View 108 44' - 60 20' (APS-C size equivalent)
Lens Construction 12 elements / 9 groups
MFD (Minimum Focus Distance) 0.24m (entire zoom range)
Diaphragm Blades 7
Filter Size 77mm
Size (Diameter x Length) 3.3 in. x 3.4 in. (83.2mm x 86.5mm)*
Weight 370g (13.1 oz)*
Max. Mag. Ratio 1:5.1 (at f=24mm)
Standard Accessory Flower-Shaped hood
Compatible Mount Canon, Nikon, Pentax, Sony
*specifications based on Nikon mount

jmhays
06-20-2008, 01:30 PM
Don,
Whatever happened to your Sigma lens? I am looking to buy this exact same lens for my a350, but now I am not so sure that I want to purchase the Sigma instead of the Tamron or the Tokina.

What did Sigma have to say about their quality control issue?

DonSchap
06-21-2008, 04:56 PM
I looked at the time and costs involved in returning the SIGMA for a "tweak" (the problem was not severe enough to give up the lens) ... and decided not to. I need the lens for my regular shooting, at events ... and most (85%) of the stuff I shoot is at distances where a snappy, sharp focus would go truly unappreciated. Indeed, I have other glass in my bag (17-50mm zoom, 90mm MACRO, 180mm MACRO) that I can use for the real sharp-looking, close-up work. Unfortunately, many others on the forum do not have that kind of fall back available to them.

The best idea I can put forth, at this juncture, is to go ahead and buy the lens and just check it out, thoroughly ... because, it looks like SIGMA certainly DID NOT do the rock solid QA we would love to see and expect in our optics. These puppies are still on the shelves, just like mine was. They need a good looking at, by an interested party (YOU) to determine if they are indeed sharp ... and if not, SEND IT BACK BEFORE YOU REALLY NEED IT.

I still have until January 2009 to get mine returned to SIGMA. If I do happen to pick up a TAMRON SP AF 10-24mm f/3.5-4.5 Di LD ... you can bet that I will then take the time (normally 2-months there and back again), because my bases will be covered, at that point.

The 10-20mm seems to be a nice lens ... but, I am still, personally, looking forward to the new TAMRON. Others may disagree ... and that's fine, but ... their glass works pretty well for what I do with it.

Good luck in your decision. We've all been there.

DonSchap
11-14-2008, 02:01 PM
Since UWA questions have reared their heads (Sean ... :) ), I thought I would roll out this thread, that discussed it. It's worth a look, in light of the new TAMRON 10-24

seanhoxx
11-14-2008, 05:22 PM
What can I say? was a very slow day at work, all our judges were out or doing writing days no hearings scheduled at all, 3 of the 6 people in my office on vacation, the sun was trying to shine, motivation wayned, sooooooooooooo photography research day!! ahh I do enjoy to see activity on the old forum.

DonSchap
01-09-2009, 02:56 PM
The SIGMA AF 10-20mm f/4-5.6 DC EX was submitted by to SIGMA Corp for repair on December 13th, 2008. It returned, today (January 9, 2009).

I then did a check to see how it measured up to the last set of images I took, comparing it. This was a tripod shot, using the A100 ... and the only item changed was the lenses. I initially set my exposure with the SIGMA ... thinking a good f/5.6 would be f/5.6 throughout the shoot. Unfortunately, not really ... apparently the manufacturer's must have some disagreement here ... because although I did nothing to the lighting, the exposure sure changed, as I swapped lenses. The TAMRON & KM shot a lot brighter, by almost a full f-stop. They actually look over-exposed ... and remember, this was a "manual shot" (M-mode) ... all settings fixed.

Here they are ... with a surprise or two @ 18mm - f/5.6 - ISO 100 - External flash set on TTL - EV=0 - FV=+1 - Manual Mode - Dsitance to subject: 10-inches

SIGMA AF 10-20 4-5.6 DC EX
43477

Konica-Minolta AF 17-35mm f/2.8-4 "D"
43478

TAMRON SP AF 17-50mm f/2.8 XR Di-II LD Aspherical (IF)
43479

TAMRON AF 18-250mm f/3.5-6.3 ZR Di-II LD Aspherical (IF)
43480

The real surprise is the comparison shot with the TAMRON 18-250mm f/3.5-6.3 lens. The "Utility Lens" turned in some excellent results ... and once again, renews my faith in its ability to deliver. A truly super "all-around" lens.


Anyway, just for review: Here is the initial SIGMA AF 10-20mm f/4-5.6 DC EX O-O-T-B shot to caused my concern and sent the lens off for manufacturer's warranty adjustment.

B4 Adjustment
43476

AFTA Adjustment
43477

The focus has definitely been improved to acceptable standards.

dr4gon
01-09-2009, 03:50 PM
Man.... acceptable but what did they do with the aperture? It's not providing an accurate reading (at least not with respect to the other lenses)

As far as sharpness goes, it looks a whole lot better!

DonSchap
01-09-2009, 04:17 PM
Man.... acceptable but what did they do with the aperture? It's not providing an accurate reading (at least not with respect to the other lenses)

As far as sharpness goes, it looks a whole lot better!


As I recall, it shot "dark" when I first got it. I would like to see some other people's comparisons of the lens to their TAMRONs.

EDIT: Okay ... after several other test shots ... between the 18-250 "all-in-one" and the 10-20 "UWA", it is more like a third of an f-stop "darker" ... when the TAMRON is set to f/6.3 ... I get the same illumination of the image at f/5.6 on the SIGMA. But, I already knew the 18-250 shot a little darker than the f/2.8 lenses. It's not of the same caliber. It's a longer, darker lens.

I will post the aperture comparisons later on, to gauge this a bit more accurately ... but, it is hard to believe. I don't even know how to complain about it to the factory guys ... because this is a design error ... not a repair. Whoa. I know the TAMRON (or KM) f/2.8s do shoot brighter ... the question is ... which is correct? What should I use as a standard? The closest PRIME I have is the Minolta AF 24mm f/2.8. Lighting is lighting, but distance does factor into the equation. There is quite a gap between 20mm and 24mm, although it may not seem like it. I suppose I could run out and just buy a SONY 20mm f/2.8 PRIME. Although, I don't think the SONY Style store has them in stock. It is not a high-demand lens, unlike the 28mm or the 50mm.

As I thought about this ... I decided to compare the TAMRON (& KM) at the equivalent 24mm with the Minolta PRIME. That will provide a direct correlation with the calibration of those lenses and the SIGMA. (BTW: The Minolta AF 24mm f/2.8 was recently cleaned and calibrated) If the TAMRON (& KM) are spot on ... SIGMA has some 'splaining to do.

Man oh man ... this definitely qualifies as "weird."

DonSchap
01-09-2009, 08:33 PM
Okay ... after conducting the snaps ... the Minolta 24mm f/2.8 set @ f/5.6 confirms the f/5.6 exposure setting of both the TAMRON & KM f/2.8 lens is correct.

Minolta PRIME 24mm f/2.8 @ f/5.6
43484

TAMRON SP AF 17~50mm f/2.8 @ f/5.6
43485

Konica-Minolta AF 17~35mm f/2.8~4 "D" @ f/5.6
43486

DonSchap
01-09-2009, 09:13 PM
So ... concluding the KM has the EV right ... a side-by-side against the SIGMA 10-20 @ 20mm - f/5.6

A: KM @ f/5.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SIGMA @ f/5.6
4348743490

B: KM @ f/6.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SIGMA @ f/5.6
4348843490

C: KM @ f/7.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SIGMA @ f/5.6
4348943490

So the question is ... which of these exposures looks like the SIGMA's f/5.6? A, B, or C?

DonSchap
01-09-2009, 09:17 PM
It's not the full stop that I seemed to have had experienced earlier ... but, it still is not as accurate as I had hoped. It's more like a f/4.5-6.3 lens, than a f/4-5.6 lens. So much for my results ... you can try this when you get yours.

With the PRIME up against it ... LOL

Minolta AF 24 @ f/5.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SIGMA 10-20 @ f/5.6 (20mm)
4349343492

f/5.6 just ain't what it used to be ... :rolleyes:

dr4gon
01-09-2009, 09:19 PM
Well from what I can tell, the sigma is certainly sharper!

I'd say F/6.3 is about right. 5.6 is pretty close, but not quite.

DonSchap
01-09-2009, 09:28 PM
I hope that last edit put it together ... it is dark. Sharp, but dark.

dr4gon
01-10-2009, 06:49 AM
Yeah I'm sure the contrast helps make it sharper too.

dr4gon
01-10-2009, 03:55 PM
In Pop Photo's Feb. 2008 issue, they rate Tamron's 10-24mm very favorably.


"With excellent-range SQF scores at the three tested focal lengths, the lens promises faultless contrast and resolving powers" ....

"slight barrel distortion...noticeable improvments over the 11-18mm

....

light falloff left the Tamron's corners by f/5.6 at 10mm, and there was no discernaible vignetting at the other tested focal lengths. WOW!

close-up performance was also stellar....

They seem to really like the lens!

The SQF table was about 1 point or less all around over the Sony (Tamron) 11-18mm tested here:

http://www.popphoto.com/cameralenses/4475/lens-test-sony-11-18mm-f45-56-dt-af-specifications-page2.html

The "size" is that megapixels?

DonSchap
02-01-2009, 09:52 PM
In Pop Photo's Feb. 2008 issue, they rate Tamron's 10-24mm very favorably.



They seem to really like the lens!

The SQF table was about 1 point or less all around over the Sony (Tamron) 11-18mm tested here:

http://www.popphoto.com/cameralenses/4475/lens-test-sony-11-18mm-f45-56-dt-af-specifications-page2.html

The "size" is that megapixels?

No, the "size" is the aperture setting on the lens. You can see that the minimum size goes up as the focal length gets longer. The chart indicates quality of image in an inch-by-inch format.

dr4gon
02-01-2009, 09:56 PM
No, the "size" is the aperture setting on the lens. You can see that the minimum size goes up as the focal length gets longer. The chart indicates quality of image in an inch-by-inch format.

haha, I'm retarded, I was thinking about that after I posted and didn't want to dig it up. dunno what I was thinking. I browse lens reviews all the time (photozone charts) :D