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04-23-2014, 10:32 AM   #211
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QuoteOriginally posted by Class A Quote
I didn't really mean to say that the thermal stability is better than metal, sorry.

I believe I was thinking about the "Thermally Stable Composite" that Sigma uses. It has the same level of shrinkage as Aluminium with very good elasticity, so it seems like a high-tech (as opposed to "cheap") material to me.

BTW, there are many OEM lenses from respected manufacturers that use "plastic" internal lens mounts.

No arguments with any of those statements.

04-23-2014, 06:33 PM   #212
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Sigma has a winnng formula

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_______________________A 50 1.4___________________________________________________________ FA 43 1.9___________________


It seems Sigma is producing lenses that are far more appealing from a marketing point of view than other companies. They focus on sharpness at wide open as opposed to peak sharpness. I am not saying their lenses are not good but other companies realise that there are trade offs. Maybe in this day and age of pixel peeping and dxo mark scores that is what other companies should be focusing on as well not just the photo's they produce. Compared to the FA 43 the sigma is slightly sharper below 2.8 above that the aging pentax clearly beats it in center resolution or am I reading these incorrectly?
04-23-2014, 07:55 PM   #213
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QuoteOriginally posted by Belnan Quote

It seems Sigma is producing lenses that are far more appealing from a marketing point of view than other companies. They focus on sharpness at wide open as opposed to peak sharpness. I am not saying their lenses are not good but other companies realise that there are trade offs. Maybe in this day and age of pixel peeping and dxo mark scores that is what other companies should be focusing on as well not just the photo's they produce. Compared to the FA 43 the sigma is slightly sharper below 2.8 above that the aging pentax clearly beats it in center resolution or am I reading these incorrectly?
It is hard to derive any solid conclusions with regards to which has better resolution from the two graphs because they were likely shot from two different cameras with different sensors. More to your point, I do believe Sigma is capitalizing on consumers obsession (and perhaps misguided perception) that best numbers=better photographs. However it does, if nothing else, give the owner bragging rights for the sharpest ...... around for a short time before it is bettered by the next best lens.
05-06-2014, 10:59 PM   #214
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But.... The bulk!! Mount this lens on a d800 and the combo weighs the same as a 645z with a longish normal... (The 75/2.8)

05-07-2014, 06:46 AM   #215
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The d800 would be faster. The 645 could be sharper... but that 75 is older so who knows.

Let's say in a perfect world the d800 is a stop and a half faster and the 645 is sharper.

Choose your poison.
05-07-2014, 07:54 AM   #216
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If you want razor sharp, you need to stop down anyway if your subject isn't completely flat ;-) I never had faster than a 50/1.7 on FF (i.e. film) and only very occasionally used f-stops below 2.8.

This lens seems like a perfectionist engineer's dream more than a photography tool to me. I'm sure it will be used to take wonderful pictures, but if one is ready to accept this amount of bulk in trade for IQ, an MF system seems more tempting. Except for the price tag, of course.
05-07-2014, 08:39 AM - 1 Like   #217
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I shoot mostly events and spend most of my time at F/4 or faster. I don't use flash and I want all the speed I can get. Working a crowded room or a stage with a busy background I want to melt away the distractions as much as possible since I can't control my background.

I want speed and sharp usable images at wide apertures. The size and weight at not really that much of an issue.
05-15-2014, 03:45 PM   #218
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I will own this lens... If it's anything like my Sigma Art 35mm f/1.4

---------- Post added 05-15-2014 at 04:51 PM ----------

Seriously, the quality (at least of my 35mm) is stellar. I've taken it through rain storms and all kinds of abuse and it just keeps delivering the goods. Sure, it's a heavy beast, but I guess I'm willing to endure that for the quality. I've had my fair share of non-art Sigma lenses, and even the best of them don't come close to the quality, both physical and IQ, of the 35mm art lens... The consistency of what it delivers beats any Pentax lens I've ever owned, though I have had Pentax lenses that best it in terms of occasional output.
If this latest 50mm release is the same... It's worth the weight, and size, and price.

But that's just my opinion.

05-16-2014, 01:10 AM   #219
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QuoteOriginally posted by Winder Quote
I shoot mostly events and spend most of my time at F/4 or faster. I don't use flash and I want all the speed I can get. Working a crowded room or a stage with a busy background I want to melt away the distractions as much as possible since I can't control my background.

I want speed and sharp usable images at wide apertures. The size and weight at not really that much of an issue.
Amen!

---------- Post added 05-16-14 at 06:11 PM ----------

QuoteOriginally posted by Ubuntu_user Quote


Seriously, the quality (at least of my 35mm) is stellar. I've taken it through rain storms and all kinds of abuse and it just keeps delivering the goods. Sure, it's a heavy beast, but I guess I'm willing to endure that for the quality. I've had my fair share of non-art Sigma lenses, and even the best of them don't come close to the quality, both physical and IQ, of the 35mm art lens... The consistency of what it delivers beats any Pentax lens I've ever owned, though I have had Pentax lenses that best it in terms of occasional output.
If this latest 50mm release is the same... It's worth the weight, and size, and price.

But that's just my opinion.
I agree, so I guess it's not JUST your opinion
05-16-2014, 06:52 PM   #220
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Will this have better IQ than the DA* 55?
05-17-2014, 02:21 AM   #221
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I suppose so, those ART series are really tempting but...
05-17-2014, 03:12 AM   #222
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QuoteOriginally posted by Newtophotos Quote
Will this have better IQ than the DA* 55?
To get an idea:

Pentax smc DA* 55 mm f/1.4 SDM review - Introduction - Lenstip.com

Sigma A 50 mm f/1.4 DG HSM review - Introduction - Lenstip.com
05-17-2014, 01:18 PM   #223
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Well, sadly this needs some perspective which is lacking on lenstips.

The graphs show results in lines per mm, so they are not normalized for sensor size (LP/PH). Generally my rule of thumb is that the same lens on same pixelcount 36x24 sensor resolves about +20% better than on 24x16 Sensor. That would mean, you have to divide the Sigma values by 1,2 to compare.

Then you also have the hugely different pixelcounts of 14,6 MPx Pentax K20D versus 22,3 MPx Canon 5D3 (153%), which means about +24% Pixel resolution in linear dimension. That again needs to be taken into account. Just look at D800 resolutions and you know what effects pixelcount has. So a division by 1,24 might be in order as well.

Suddenly the DA*55 does look quite good.
05-17-2014, 04:22 PM - 1 Like   #224
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QuoteOriginally posted by HavelockV Quote
Well, sadly this needs some perspective which is lacking on lenstips.

The graphs show results in lines per mm, so they are not normalized for sensor size (LP/PH). Generally my rule of thumb is that the same lens on same pixelcount 36x24 sensor resolves about +20% better than on 24x16 Sensor. That would mean, you have to divide the Sigma values by 1,2 to compare.

Then you also have the hugely different pixelcounts of 14,6 MPx Pentax K20D versus 22,3 MPx Canon 5D3 (153%), which means about +24% Pixel resolution in linear dimension. That again needs to be taken into account. Just look at D800 resolutions and you know what effects pixelcount has. So a division by 1,24 might be in order as well.

Suddenly the DA*55 does look quite good.
It's the opposite of that. lines/mm are normalized for sensor size, and more-closely evaluate the lens performance only. Lines/ph is NOT normalized for sensor size, and combine the lens performance with the sensor size.

15MP to 22MP is worth ~10-20% on some lenses. FF is worth ~30% linearly on some lenses, in a perfect scenario FF would be worth ~52% more linearly.

Dr. Camera: Have the recent improvements in sensors changed the optimum sensor size?


The 55mm is good. The sigma is better, basically class-leading performance.
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