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09-11-2012, 01:12 PM   #16
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QuoteOriginally posted by Fontan Quote
There is an easy explanation; SDM broke during the testing.
Well it is just this lens that has the least problems with SDM, probably due to the low weight compared to the large heavy zoomlenses.

09-11-2012, 01:39 PM   #17
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It is a bit lower in resolution, but it scores the same as the Sigma 50 1.4 on the D7000 and better than most 50 1.x on equivalent cameras.

For comparison:
DA*55 F1.4 on k-5 - 17 (Resolution 44lp/mm)
Canon EF 50 1.4 on 7D - 15 (Resolution 50lp/mm)
Nikon 50 1.4 on D7000 - 18 (Resolution 51lp/mm)
Sigma 50 1.4 on D7000 - 17 (Resolution 48lp/mm)
Nikon AF-S 50 1.4G on D7000 - 18 (Resolution 50lp/mm)
Nikon AF-S 50 1.8G on D7000 - 12 (Resolution 43lp/mm)

So the DA*55 performs overall as well as the other brands 50s, is a bit more expensive, but has WR. I personally chose to get the Sigma 50 over the DA*55 a short while back because of price, HSM, and sharpness - several users stated that their Sigma 50 was marginally sharper than the DA*55. Seems like that's accurate per DXO - but sharpness is not everything.

Last edited by JinDesu; 09-11-2012 at 01:56 PM.
09-11-2012, 02:19 PM   #18
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QuoteOriginally posted by JinDesu Quote
It is a bit lower in resolution, but it scores the same as the Sigma 50 1.4 on the D7000 and better than most 50 1.x on equivalent cameras.

For comparison:
DA*55 F1.4 on k-5 - 17 (Resolution 44lp/mm)
Canon EF 50 1.4 on 7D - 15 (Resolution 50lp/mm)
Nikon 50 1.4 on D7000 - 18 (Resolution 51lp/mm)
Sigma 50 1.4 on D7000 - 17 (Resolution 48lp/mm)
Nikon AF-S 50 1.4G on D7000 - 18 (Resolution 50lp/mm)
Nikon AF-S 50 1.8G on D7000 - 12 (Resolution 43lp/mm)

So the DA*55 performs overall as well as the other brands 50s, is a bit more expensive, but has WR. I personally chose to get the Sigma 50 over the DA*55 a short while back because of price, HSM, and sharpness - several users stated that their Sigma 50 was marginally sharper than the DA*55. Seems like that's accurate per DXO - but sharpness is not everything.
The important thing is to pay attention to whether the 50s are being shot on full frame or APS-C, because that really does effect the final number. I like the 55, although I don't generally shoot wide open, choosing rather to stop it down to f2. Seems to be as sharp as the FA limiteds at that point which is sharp enough for me.
09-11-2012, 02:21 PM   #19
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QuoteOriginally posted by Rondec Quote
The important thing is to pay attention to whether the 50s are being shot on full frame or APS-C, because that really does effect the final number. I like the 55, although I don't generally shoot wide open, choosing rather to stop it down to f2. Seems to be as sharp as the FA limiteds at that point which is sharp enough for me.
Not just APS-C - preferably a similar sensor to the k-5 (D7000, for example). This is because some of the older and lower MP sensors will reduce the values.

09-11-2012, 02:40 PM   #20
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Btw, don't other brands have 55mm primes? Or is this focal length a Pentax special, like some others?
09-11-2012, 02:43 PM   #21
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QuoteOriginally posted by Na Horuk Quote
Btw, don't other brands have 55mm primes? Or is this focal length a Pentax special, like some others?
It is a lens optimized for portrait, 55mm on APS-C being more or less the same as 85mm on FF.
09-11-2012, 02:46 PM   #22
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QuoteOriginally posted by thibs Quote
It is a lens optimized for portrait, 55mm on APS-C being more or less the same as 85mm on FF.
That may be right, but the 55mm has tradition since the Takumar days. This also isn't a reason why other brands don't have this focal length, after all, they sell plenty crop sensor cameras.

09-11-2012, 03:19 PM   #23
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QuoteOriginally posted by Rondec Quote
The important thing is to pay attention to whether the 50s are being shot on full frame or APS-C, because that really does effect the final number.
All else the same - center resolution reported by DxO doesn't depend on format, as they report lp/mm.

All else the same - center resolution reported by Photozone depends on format, as they report lp/ph.

I have no interest in figuring out how they determine their '17' score because it cannot be correlated to how useful a tool any particular lens can be.
09-11-2012, 04:11 PM   #24
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I don't think they did a real shotting with the DA*55.

It's a hell of a lens, my favorite so far, that is ... just miles ahead any other standard lens.
09-11-2012, 04:36 PM - 1 Like   #25
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How likely is it that DXO are the authority for sensor performance, yet get it completely wrong on lens comparisons? I'm honestly wondering... can Pentax lenses really be this average compared to the other systems? Are we delusional holding up the K-5 DXO score, yet ignoring the DXO lens tests which show our lenses being sub-par.
09-11-2012, 04:58 PM   #26
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QuoteOriginally posted by twitch Quote
How likely is it that DXO are the authority for sensor performance, yet get it completely wrong on lens comparisons? I'm honestly wondering... can Pentax lenses really be this average compared to the other systems? Are we delusional holding up the K-5 DXO score, yet ignoring the DXO lens tests which show our lenses being sub-par.
Well, no, I don't think we're being delusional at all. We're just going on experience. We all know that the K5 sensor is indeed pretty fantastic. Many of us also know that the 55 is the bees knees, too. Real-world use tells us that DXO was right about the sensor and wrong about the lens. This is also why my bike has components from about six different manufacturers. Rarely can one outfit do a multitude of things well.
09-11-2012, 06:09 PM   #27
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QuoteOriginally posted by twitch Quote
How likely is it that DXO are the authority for sensor performance, yet get it completely wrong on lens comparisons?
They don't consider usage, don't consider bokeh, and try to boil every lens down to one number without regard to these and other factors. I'm not sure that they consider contrast, etc., of a lens although that might be in there.

Let's say you made an average resolution 600mm f/1.4 manual focus lens. It would score awesomely.

Let's say you made an average resolution 600mm f/4 AF lens. It would score poorly.

Let's say you made a sharp lens that rendered incredibly at 15mm f/4. It would score terribly.
09-11-2012, 06:12 PM   #28
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Yep - they weigh Tstop really highly, from what I've seen - and it really skews some numbers.
09-11-2012, 06:16 PM   #29
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But isn't it the same for all lens makers, what makes Pentax lens unique that they score badly?
09-11-2012, 06:21 PM - 1 Like   #30
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QuoteOriginally posted by twitch Quote
But isn't it the same for all lens makers, what makes Pentax lens unique that they score badly?
Some of Pentax's best lenses (IMO) are the best because of flare resistance, rendering/contrast, and bokeh.

flare resistance is actually a negative in DxOmark world (assuming more flare resistance is a bit less transmissive of a coating). The other two aren't scored at all.

Pentax's best lenses are, except for the 5Xmm f/1.4, slower than competing brands.

I think Pentax makes lenses for use cases rather than scoring.
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