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08-24-2010, 11:33 AM   #316
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QuoteOriginally posted by Russell-Evans Quote
We all just want value for our money spent. Although Pentax can set the price, we the buyers, determine the value. That's the reason street prices are what they are. That's the way it is with all products. It is Pentax' job provide value, whether real, or not, for their products. They survive based on that and that alone. It is nothing personal and it is nothing new.

Thank you
Russell
Pentax also has the right to value their cameras for what they think it is worth. I would be willing to bet that the #1 or #2 reason many of us are with Pentax is because you get a lotta bang for your buck despite not getting the top quality of Canon or nikon.

08-24-2010, 11:46 AM   #317
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QuoteOriginally posted by Agnostic Quote
That's what Sony states. Might be somewhat optimistic under real world conditions.
Particularly when dust will be sticked on the semi-transparent mirror; what a nightmare to clean it
08-24-2010, 03:46 PM   #318
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I'm more worried about the translucent (or, worse yet, semi-translucent) mirror.

What the heck is that? I would expect that the last thing we need is glass that diffuses the light as it passes through.

But I'm not an optical engineer. Maybe translucent means something different to them. Maybe DPR isn't careful in their reviews. Oh. Never mind ....
08-24-2010, 05:40 PM   #319
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QuoteOriginally posted by glanglois Quote
I'm more worried about the translucent (or, worse yet, semi-translucent) mirror.

What the heck is that? I would expect that the last thing we need is glass that diffuses the light as it passes through.
That's Sony's own terminology. (Well, semi-translucent isn't, but translucent mirror is.)

Sony Electronics News and Information

If you check the dictionary, translucent doesn't necessarily mean that light is diffused as it passes through. Yes, that's one of the meanings, but it can also mean that light is partially transmitted, and partially reflected.

As for why they called it that, note the trademark symbol. They probably couldn't have trademarked pellicle mirror, as that's been in usage for decades.

08-25-2010, 01:05 AM   #320
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QuoteOriginally posted by blende8 Quote
30% = 3/5 ev
Indeed it's not 1/3 Ev. But 3/5 Ev is a bit exaggerated, since the relation is not linear.

50% is 1 Ev less than 100%
25% is 2 Ev less than 100%
12.5% is 3 Ev less than 100%

So where does 70% sit exactly? A bit of play in Excel (Excel's goal seeker is great for compensating my mathematical shortcomings ) tells me that 70% is 0,514573 Ev less than 100%. So slightly more than half a stop, which is not really the same as "roughly 1/3 Ev"...

So: the gain the A55 needs to apply is more than 1/3 Ev, it's actually 1/2 Ev. Which means more advantage for using this sensor in a DSLR such as the rumoured K-5. There's not much between 1/2 and 1/3, but it is significant.

Wim
08-25-2010, 01:26 AM   #321
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You are right, Wim.

And dpreview corrected it in their review.

Last edited by blende8; 08-25-2010 at 02:27 AM.
08-25-2010, 03:23 AM   #322
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QuoteOriginally posted by wll Quote
25,600 high ISO in JPG only and multi shot ?

I hope this is not the case for the K-5. The reason you use 25,600 is for a concert situation or other where you need fast ISO to stop movement.

I can tell you I'm not using ISO 25,600 for landscapes or architecture, I could use it for candle lit situations or folks out of the spotlight that are in the shadows.

I hope Pentax has ISO 25,600 that is usable and not just a gimmick.

wll
From the sound of it it is a multishot combined into one. To me it seems a bit like an experimental feature, like the Hi-speed mode in K20D... Can be useful at times, but not something you would use every day.

And if the evolution of high ISO noise output stays the same as it has been the last years, I would expect it to look like K-x and similar bodies at ISO12800. That is, slightly better than K20D / K-7 @ ISO6400 in RAW.
08-25-2010, 04:28 AM   #323
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25600 ISO in K-5 is likely not to be multishot only.
In fact multishot is a Sony only feature as far as we can tell.
the fact that the Pentax camera will be getting 60% more light to the sensor from a single exposure tells me that the 12800 will be very good, and 25600 will be usable in emergencies.
The great thing about this new sensor is the lack of banding, and increased DR. If you have DR and no banding at higher ISO, then that makes them usable.
DPreview already think the A55 performs better than the NEX5 at ISO higher than 3200. this leaves us with a camera that is at least a stop better than what the K-x can produce (take into account what downsizing an image can do to noise) IMO.

08-25-2010, 05:03 AM   #324
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@Steelski
Hmmm, isn't dpreview talking about a ratio of 3/7? So 30% of light is reflected to the AF sensor and 70% of light passes through the translucent mirror to the CMOS sensor.

I think most of you (I hope I'm wrong) are looking at this situation the wrong way around.
Let's take a SLT and SLR camera and put them in the same environment with the same lighting. So for example the parameters on a SLR would be f/2.8 1/500s ISO100 ... on the SLT, these parameters would be (roughly) f/2.5 1/500s ISO100 or f/2.8 1/400s ISO100 or f/2.8 1/500 ISO125.
So it's sort of like using a C-POL filter on a SLR but with even less light loss. In fact, someone should try this and see if the parameters even change because the light loss is so small.

My point is that there should be no difference in ISO performances between a SLR and a SLT it's just that in the same light conditions a SLT will have to work a bit harder to get the same exposure but not that much harder since the difference is only 3/5 of a stop.

Of course the translucent mirror could result in worse color reproduction but we'll just have to wait and see the images taken with the same sensor on a SLR and compare the RAW data.

I'll probably wait this and won't upgrade, because my K-7 is only a year old (love the tool BTW, it almost made me forget that I have a K10D ).

Now, for lenses ... I'm hoping for some UWA prime upgrades that start at 10 or 12mm.
08-25-2010, 05:32 AM   #325
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Yeah, but from what I read Sony has upped the gain somewhat to compensate for the light loss. That would negatively affect the signal to noise ratio.
08-25-2010, 05:45 AM   #326
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Sounds like something Sony would do.
08-25-2010, 06:30 AM   #327
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QuoteOriginally posted by Agnostic Quote
Yeah, but from what I read Sony has upped the gain somewhat to compensate for the light loss. That would negatively affect the signal to noise ratio.
Exactly, Sony boost gain to compensate the 60% (3/5ths of one stop) light loss. thats like shooting at ISO 6400 when you could be shooting at ISO 4000 or close to. there is even proof of this.
Go to imaging resources dot com. and use the comparometer to compare the New A560 vs the new A33. both use the same chip. one uses gain to get the same ISO. the result is that one looks noticeably worse. Also compare the A33 vs the A55 in the office reading book scene at 12800. the lady's skin is so much better on the A55, all adding up for the 16.2 MP chip. Almost 1 stop advantage vs the 14.2 MP chip (probably about 3/4s better in color and DR) add the 3/5ths of a stop light you gain from losing the see through mirror and you get a chip that is very good (almost D700 good) who knows how much Pentax will also be able to extract from the chip with better internal components.
I would guesstimate a full stop better than the K-x. if not slightly more. with better color and a real ISO 100.
08-25-2010, 06:36 AM   #328
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For the people wondering about the effect of the translucent window, just compare the images from a33 and a560 in the Imaging Resource Comparometer: Imaging Resource "Comparometer" ™ Digital Camera Image Comparison Page
For what I can see, there is about 1/2EV of difference, exactly what was expected ("a33 iso 12800" better than "a560 iso 6400" but worse than "a560 iso 12800")
Edit: grilled by Steelski! :P
08-25-2010, 06:37 AM   #329
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QuoteOriginally posted by Steelski Quote
Exactly, Sony boost gain to compensate the 60% (3/5ths of one stop) light loss.
Correction (see my earlier post, and the exchange on DPR): 30% light loss because of the mirror, this corresponds to roughly 1/2Ev (half a stop) less light reaching the sensor. Sorry to repeat this, just trying to avoid wrong information being propagated.

So it's not as dramatic as what you write, but of course the deductions from the resulting images stand.

Wim
08-25-2010, 08:09 AM   #330
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Remember guys that a lot of people still carry a Ist DL or DS, a K100, a K200 or a K10 and a K7 with a better AF will be a go for them (if one has a K20 perhaps the jump could not be appealing enough).

And when I say "poeple" I actually include me
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