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Author Topic: Pentax K5 field review on its way?  (Read 15412 times)

fredjeang

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Pentax K5 field review on its way?
« on: October 02, 2010, 04:09:36 pm »

Hi,

A field review of the new Pentax K5 coming soon?

« Last Edit: March 30, 2011, 10:43:26 am by fredjeang »
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ndevlin

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Re: Pentax K5 field review on its way?
« Reply #1 on: October 04, 2010, 09:25:13 am »

Hey Fred,

As someone who occasionally writes about cameras and other topics here, one thing that has struck me is that there is just much less interesting to say about gear nowadays, and indeed about digital imaging generally. 

As the digital revolution was unfolding, the news was unceasingly interesting as we followed every twist and turn. Is this new camera an amazing breakthrough? Has some nagging issue been solved? Has teh next quality barrier been broken?

But now that the revolution is over and a fairly stable status quo has set in, the technical side of things has become notably less interesting to talk about. Beyond, "Yup, it's a camera" there's not a great deal to say about most new offerings these days.  Indeed, Michael made this absically this same point some time ago when he scaled-back on straight-up equipment reviews, I believe.

This may be a blessing, because we can get back to talking more about photography, substantively. That's a harder topic to address from many standpoints, and requires actual talent and the courage to actually go out and take photographs. Sitting in front of one’s computer talking about megapixels is much easier. It’s kind of like the difference
between growing your own food and eating a bag of Doritos. One is much healtheir and ultimately fulfilling, whereas the other is easier and more fun ni the moment.

All of this is a long answer to a polite request to field test the K-5. I can’t speak for Michael, but it might happen. Certainly the coming changes to the site make it much likelier that someone will take up the challenge.

Personally, I will be tied up with the 645D (because the revolution is still in full-swing in medium format  ;D) , but time for a K-review might be possible.

I guess it all boils down to this: other than ‘yup, it’s a camera’, what do you really want to know about it that you can’t tell or extrapolate for the specs and collective expereience to date?

Cheers,

- N.
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Nick Devlin   @onelittlecamera        ww

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Re: Pentax K5 field review on its way?
« Reply #2 on: November 07, 2010, 05:22:28 pm »

I'm realy looking forward now read the Reviews as the camera is generaly available. Perhaps I will do my own anyway, as I should have the K-5 later this week and I hope to catch the last of Autumn before it gets blown away.

I've been following the Forums in DPReview, and since the DxOMark sensor tests have been released it is causing quite a degree of interest - And not just in the Pentax Forums. It could well be using a SONY Sensor capable of a usable 14 stop! dynamic range at ISO 80. Also a very useable clean 1600ASA with 10 stops of DR (K-7 only managed 7) having signal to noise ratios close to the full frame Nikons.  This is a big big step forward. And not just for Pentax if this sensor becomes more widely available.  We might just have the best landscape camera, this side of MF, of any APS-C camera in 2011. And not forgetting it's water resistant construction. Very imortant, if like me you walk 5-10 miles a week throuought the year in all weathers.

Anyone want a K-7? :-\

Pete.
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feppe

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Re: Pentax K5 field review on its way?
« Reply #3 on: November 07, 2010, 05:36:34 pm »

We might just have the best landscape camera, this side of MF, of any APS-C camera in 2011.

To get this perfectly clear: DxOMark ranks K5 as #1 APS-C sensor by a wide margin, has higher score and DR than 5DII, has exactly the same score as D3s, wider DR than D3x, and wider DR and low-light performance than any Phase camera they've tested. I'm sure this causes cognitive dissonance in many, and am surprised we haven't seen more discussion about the sensor/camera here.

It's going to be interesting to see what the next generation from Canon and Nikon brings.

fredjeang

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Re: Pentax K5 field review on its way?
« Reply #4 on: November 07, 2010, 06:16:46 pm »

I remember having compared at 800 isos some Pentax Kx pics (entry level) to the Canon 7D at the same iso, same subject and the Kx was beating the Canon in all aspects.
Yeah, it seems that they really have something with the K5.

I like more and more the Pentax brand. They don't make a lot of noise, nothing ground breaking but they improve step by step within a really helphy politic. I won't be surprise to see Pentax again very soon in the hands of the pros and serious amateurs sphere.
« Last Edit: November 07, 2010, 06:20:47 pm by fredjeang »
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Ray

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Re: Pentax K5 field review on its way?
« Reply #5 on: November 07, 2010, 06:23:35 pm »

To get this perfectly clear: DxOMark ranks K5 as #1 APS-C sensor by a wide margin, has higher score and DR than 5DII, has exactly the same score as D3s, wider DR than D3x, and wider DR and low-light performance than any Phase camera they've tested. I'm sure this causes cognitive dissonance in many, and am surprised we haven't seen more discussion about the sensor/camera here.

It's going to be interesting to see what the next generation from Canon and Nikon brings.

But that's just blah! blah! technical nonsense, isn't it? What counts is the field report. Can you use the camera in winter wearing gloves? Does your nose accidentally move a switch when you press your face to the camera. Does it feel nice in the hands? Is the camera well-balanced or does it feel a bit awkward as though it were designed by an engineer.

These are the questions for the true artist. We can't expect the artist to adapt to the quirks and peculiarities of the camera.
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Mark D Segal

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Re: Pentax K5 field review on its way?
« Reply #6 on: November 07, 2010, 07:32:26 pm »

Ray - you make a very good point. Statistics and hands-on reviews are complementary. What kind of intrigues me about the K5, all other considerations aside, is the relationship between the DxO data and the price. On the surface of it, this really looks good, for whatever that turns out to mean in real-world image making. So while I see Nick's point very well, I think there will continue to be particular aspects of certain cameras, while they no longer turn the world upside-down, which will nonetheless interest those looking to maximize value for money relative to the use they will make of the alternative cameras they can consider.
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Mark D Segal (formerly MarkDS)
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feppe

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Re: Pentax K5 field review on its way?
« Reply #7 on: November 07, 2010, 08:05:32 pm »

But that's just blah! blah! technical nonsense, isn't it? What counts is the field report. Can you use the camera in winter wearing gloves? Does your nose accidentally move a switch when you press your face to the camera. Does it feel nice in the hands? Is the camera well-balanced or does it feel a bit awkward as though it were designed by an engineer.

These are the questions for the true artist. We can't expect the artist to adapt to the quirks and peculiarities of the camera.

In case you're not trolling this time: DxO only tests for sensor (and lens) IQ on several metrics, and leave the field reports for LL and other similar sites. Their tests are definitely technical, but far from nonsense, but obviously there's much more to a camera than DR, color depth and SNR.

Ray

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Re: Pentax K5 field review on its way?
« Reply #8 on: November 07, 2010, 09:18:53 pm »

Ah! I see that none of you picked up the sarcasm in my comment  ;D . I was actually having a dig at Fred.

I do understand that DXOMark tests only the fundamental performance characteristics of the sensor, even bypassing the lens.

What I find very odd is that certain photographers whose equipment does not get favourable scores on the DXOMark website, or at least gets scores that are below their own expectations, tend to attack the validity of the results without showing any evidence of their own that might give some credence to an opinion that DXO results are misleading, incomplete nonsense or plain wrong.

I, myself, would find it very interesting and illuminating if someone were to demonstrate, with 100% crops, that camera A, for example, has a full stop better DR (or lower noise) than camera B, despite DXOMark tests indicating the reverse, that camera B has better DR.

We could then make some progress and perhaps find out what significant attributes of sensor performance DXO might be overlooking and not testing. Or, we might find out just how much better one particular brand of RAW conversion software is compared with another.

Whenever I've taken the trouble to compare RAW converters, I've found that sometimes the differences can initially appear to be significant when using the default settings with each converter, but not nearly as significant after making appropriate adjustments to emulate the effect of one converter with another. For example, Bibble or DPP might produce slightly sharper results than ACR, but with the trade-off of more noise.

After reducing noise in the Bibble conversions to the ACR level, or, after increasing noise by more sharpening in ACR and other adjustments, the final results are very close, in my experience.
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Ray

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Re: Pentax K5 field review on its way?
« Reply #9 on: November 07, 2010, 10:42:24 pm »

Dear me! The following DXOMark results, which I reproduce for editorial purposes, hoping that DXO do not object, must be very embarrassing for those who bought a P65+ on the basis of its superior dynamic range.

We now seem to have the extraordinary situation whereby a 16mp cropped format DSLR appears to have in excess of a full stop greater DR at base ISO than the 60mp 645 P65+ with 6x the sensor area of the K5.

How is this possible?

I hope that, instead of getting purple in the face, or dismissing the results with nose in the air, an owner of a P65+ back might take the trouble to buy or borrow a K5 and show us all how successful Capture One is, with its secret processing algorithms, at exceeding the DR of the K5, when used to convert the P65+ RAW file.

If one examines the attached image of the DXOMark graphs (P65+ in yellow), you should also note that, even when the P65+ is in sensor+ mode (binned 15mp), the K5 still has over a stop more DR. However, if anyone is thinking of testing this, you should compare the P65+ at ISO 1600 with the K5 at ISO 800, for equal real ISO, equal shutter speed and equal T-stop.

We won't mention the DoF implications. If I were to ask you to equalise DoF, it would possibly be just too much. I do have some compassion, ya know!  :)

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ErikKaffehr

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Re: Pentax K5 field review on its way?
« Reply #10 on: November 08, 2010, 12:48:56 am »

Hi,

DR as defined by DxO is essentially full well capacity divided by readout noise. Both are normally conveniently measured in electrons.

The indication from DxO results may be that whoever makes the Pentax K5 sensor increased well capacity on a small pitch sensor significantly, that would be significant progress.

Best regards
Erik


I'm realy looking forward now read the Reviews as the camera is generaly available. Perhaps I will do my own anyway, as I should have the K-5 later this week and I hope to catch the last of Autumn before it gets blown away.

I've been following the Forums in DPReview, and since the DxOMark sensor tests have been released it is causing quite a degree of interest - And not just in the Pentax Forums. It could well be using a SONY Sensor capable of a usable 14 stop! dynamic range at ISO 80. Also a very useable clean 1600ASA with 10 stops of DR (K-7 only managed 7) having signal to noise ratios close to the full frame Nikons.  This is a big big step forward. And not just for Pentax if this sensor becomes more widely available.  We might just have the best landscape camera, this side of MF, of any APS-C camera in 2011. And not forgetting it's water resistant construction. Very imortant, if like me you walk 5-10 miles a week throuought the year in all weathers.

Anyone want a K-7? :-\

Pete.
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fredjeang

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Re: Pentax K5 field review on its way?
« Reply #11 on: November 08, 2010, 03:59:15 am »

Ah! I see that none of you picked up the sarcasm in my comment  ;D . I was actually having a dig at Fred.

I perfectly understood the "hidden message" Ray ;but I always liked your sense of "british" humour.

Well, about DxO, I was reading some older threads in Lu-La much before I joined the forum and there are many members that also critisized the dxo approach from the very beginning, so that's not new indeed and I'm far from being the only one. Probably the oldest members have done this in the past and gave up now.

If you read my posts, you will see that what I criticize is not the DxO itself but the recuperation-interpretation of those datas in the argumentation. DxO is okay, they want to do lab testings, well that's perfectly fine to me.  

Back to the Pentaxes, they are very small cameras. What I can tell you is that for example in video shooting, it is much more efficient than the Canon 5D MK2. Some days ago I shooted video with both and the compactness-balance in hands allows to do much more things with ease. Their choice of motion jpegs have been criticized, but in fact it's heavy files but quality is kept higher and you can edit with all non-linear editors without compatibility problems. There are also tricks to use manual approach. In short, much simpliest than the 5D but more efficient than it seems at first. Pentax is pretty much hassle-free.


Also, and that's a very interesting point in the Pentax politics: compatibility with all their lenses in history (almost all), included the 645 series and all third-party K mount, except the Ricoh, never put a Ricoh lens on a Pentax digital if you don't know the trick to do before mounting it. (645 are allowed in 35mm mount, not the contrary of course).
A pentax A serie for example works in full automatic and you still have focus confirmation etc...so E-bay's a place to check regularly for Pentax owners.

When they will come with a full frame dslr, they might take a lot of market parts to Canikon.
« Last Edit: March 26, 2011, 02:10:58 pm by fredjeang »
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Ray

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Re: Pentax K5 field review on its way?
« Reply #12 on: November 08, 2010, 10:39:24 am »

I perfectly understood the "hidden message" Ray ;D but I always liked your sense of "british" humour.

Great! You are very perceptive, Fred  ;D .

Quote
Well, about DxO, I was reading some older threads in Lu-La much before I joined the forum and there are many members that also critisized the dxo approach from the very beginning, so that's not new indeed and I'm far from being the only one. Probably the oldest members have done this in the past and gave up now.

It's easy to criticize, but not always easy to provide evidence to justify one's criticism.

Quote
If you read my posts, you will see that what I criticize is not the DxO itself but the recuperation-interpretation of those datas in the argumentation. DxO is okay, they want to do lab testings, well that's perfectly fine to me.

By 'recuperation-interpretation', I presume you are referring to the practical results in the field. Do the field results reflect the DXO comparisons?

The only way to find out is to make comparative tests in the field. One doesn't have to photograph boring test wedges on a chart on a wall in the studio.

One can wade into the deep forest where highlights are bright and shadows are deep. See which camera delivers both perfectly exposed clouds, and sharp leaf litter in the undergrowth. It's not difficult if you abide by a few rules. Get the same FoV, the same DoF and the same shutter speed.


Quote
Back to the Pentaxes, they are very small cameras. What I can tell you is that for example in video shooting, it is much more efficient than the Canon 5D MK2. Some days ago I shooted video with both and the compactness-balance in hands allows to do much more things with ease. Their choice of motion jpegs have been criticized, but in fact it's heavy files but quality is kept higher and you can edit with all non-linear editors without compatibility problems. There are also tricks to use manual approach. In short, much simpliest than the 5D but more efficient than it seems at first. Pentax is pretty much hassle-free.

A few weeks ago I was seriously considering the purchase of a 5D Mk2, but was hesitant because I really thought that maybe I should wait for the Mark3. The problem is, I don't have any camera that produces high quality HD video. The 7D, or more recent 60D, are alternative options, but I already have the 15mp 50D and would like significantly improved 'still image' performance as well as video.

The 5D2 produces better image quality than these cropped formats, even at base ISO, so that is the preferred option, until I just recently checked out the DXOMark website.

Oh! My God! The Pentax K5 at base ISO has over two stops (yes, that's over two full stops) higher DR than the Canon 5D2. I can't believe it!

Supposing I'd already bought a Canon 5D2, would I be cursing and swearing? Would I be blasting DXO for the irrelevance of their data?

You see the problem? This is why I don't pay much attention to criticisms of DXO results that are not supported by careful and rigorous comparisons that either provide the RAW images for download, or show 100% crops of relevant areas of the images.


Quote
Also, and that's a very interesting point in the Pentax politics: compatibility with all their lenses in history (almost all), included the 645 series and all third-party K mount, except the Ricoh, never put a Ricoh lens on a Pentax digital if you don't know the trick to do before mounting it. (645 are allowed in 35mm mount, not the contrary of course).
A pentax A serie for example works in full automatic and you still have focus confirmation etc...so E-bay's a place to check regularly for Pentax owners.

Lenses are extremely important. You can't take a photo without one. The attached image of the DXO comparisons of the 5D2, K5 and D7000 demonstrate that the Nikon D7000 is virtually on a par with the K5.

Since I already have a very good Nikkor lens, the 14-24/2.8, and am contemplating the purchase of the new 24-120/F4, the D7000 would be the better option for me. I'm also a bit confused about the 'Pentax K5 smoothed' figures on the DXO graphs. Can anyone explain this to me? Is high ISO performance not quite as good as it's cracked out to be?


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Mark D Segal

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Re: Pentax K5 field review on its way?
« Reply #13 on: November 08, 2010, 11:09:23 am »

Ray, looking at this page, http://www.dxomark.com/index.php/eng/Camera-Sensor/Sensor-rankings/Sheet-view, the overall scores (and the DR scores for Landscape) between Phase P65/P40 and Nikon D3x are so close that you wouldn't see the difference in a print due to any of these factors. Differences in lens quality will get you long before any differences in these specs. In these conditions the main advantage conferred by MF is that you can print cropped areas much larger or the full frame yet much larger still at higher quality than you can from a high-end DSLR. MF has traditionally not performed as well as the better DSLRs for very high ISO work, and that shows through in the DxO ranking for "Sports" - but I wouldn't want to be using a Phase system for sports photography anyhow - not its forte; this system is best used on a tripod at lower ISO. Horses for courses.
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fredjeang

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Re: Pentax K5 field review on its way?
« Reply #14 on: November 08, 2010, 11:52:14 am »

Great! You are very perceptive, Fred  ;D .

It's easy to criticize, but not always easy to provide evidence to justify one's criticism.

By 'recuperation-interpretation', I presume you are referring to the practical results in the field. Do the field results reflect the DXO comparisons?

The only way to find out is to make comparative tests in the field. One doesn't have to photograph boring test wedges on a chart on a wall in the studio.

One can wade into the deep forest where highlights are bright and shadows are deep. See which camera delivers both perfectly exposed clouds, and sharp leaf litter in the undergrowth. It's not difficult if you abide by a few rules. Get the same FoV, the same DoF and the same shutter speed.


A few weeks ago I was seriously considering the purchase of a 5D Mk2, but was hesitant because I really thought that maybe I should wait for the Mark3. The problem is, I don't have any camera that produces high quality HD video. The 7D, or more recent 60D, are alternative options, but I already have the 15mp 50D and would like significantly improved 'still image' performance as well as video.

The 5D2 produces better image quality than these cropped formats, even at base ISO, so that is the preferred option, until I just recently checked out the DXOMark website.

Oh! My God! The Pentax K5 at base ISO has over two stops (yes, that's over two full stops) higher DR than the Canon 5D2. I can't believe it!

Supposing I'd already bought a Canon 5D2, would I be cursing and swearing? Would I be blasting DXO for the irrelevance of their data?

You see the problem? This is why I don't pay much attention to criticisms of DXO results that are not supported by careful and rigorous comparisons that either provide the RAW images for download, or show 100% crops of relevant areas of the images.


Lenses are extremely important. You can't take a photo without one. The attached image of the DXO comparisons of the 5D2, K5 and D7000 demonstrate that the Nikon D7000 is virtually on a par with the K5.

Since I already have a very good Nikkor lens, the 14-24/2.8, and am contemplating the purchase of the new 24-120/F4, the D7000 would be the better option for me. I'm also a bit confused about the 'Pentax K5 smoothed' figures on the DXO graphs. Can anyone explain this to me? Is high ISO performance not quite as good as it's cracked out to be?



The fact that the K5 and the D7000 are sharing (I think), the same Sony sensor it's not surprising that they perform quite similar.
According to your comparaison with the 5D2, on the video session I did, there are differences. Visual differences. The 5D is a FF sensor and features 5MP more than the K5 and 9MP more that the camera involved. Differences are cristal clear in low-light and also the D.O.F you can obtain is more narrow with the 5D. In post-prod you would be much more limited with the K5 or the D7000. The D7000 seems to be an extremely good overall product. The 5D2 for stills has certainly much more to give for the money. We are talking about a 2000euros camera.
But if you already have Pentaxes lenses, the K5 is probably a very good choice. If not, I would probably stick in CaniKon
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Ray

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Re: Pentax K5 field review on its way?
« Reply #15 on: November 10, 2010, 01:24:38 am »

Ray, looking at this page, http://www.dxomark.com/index.php/eng/Camera-Sensor/Sensor-rankings/Sheet-view, the overall scores (and the DR scores for Landscape) between Phase P65/P40 and Nikon D3x are so close that you wouldn't see the difference in a print due to any of these factors. Differences in lens quality will get you long before any differences in these specs. In these conditions the main advantage conferred by MF is that you can print cropped areas much larger or the full frame yet much larger still at higher quality than you can from a high-end DSLR. MF has traditionally not performed as well as the better DSLRs for very high ISO work, and that shows through in the DxO ranking for "Sports" - but I wouldn't want to be using a Phase system for sports photography anyhow - not its forte; this system is best used on a tripod at lower ISO. Horses for courses.

Mark,
Thanks for the link to that summary of all cameras tested by DXO. It's the first time I've looked at the whole lot with their rankings. I always go straight to the graphs for selected cameras I want to compare.

Did someone on that 'pro-business' MFDB forum advise recently that it was better to test cameras for oneself before making a purchasing decision? I'm surprised such people have any time left to make money, if that's their approach.  ;D

Of course, I understand your point completely that the higher pixel-count DBs, whatever the DXOMark rankings for DR, will deliver higher resolution images with smoother tonality and better color when they are used in good lighting.

The DXO test results show that at normalised print sizes, all the other attributes of image quality that they test (SNR, tonal range, color sensitivity), are better by a noticeable margin at base ISO. And we don't need to be convinced that 60mp on a large sensor delivers better resolution than 24mp on a smaller sensor.

It's true also that the high pixel-count DB retains its advantage when it's necessary to crop an image (compared with a DSLR image that's also cropped). However, this may not be an advantage if the reason for the need to crop is due to a lack of lens flexibility; a lack of a useful zoom range, or a lack of a sufficiently long lens for the composition.

For example, if you were to crop a P65+ image to the same file size as the D3X image, perhaps because you needed a 500mm lens but only had a 300mm lens, then all image quality advantages of the P65+ would be lost, even at base ISO.
Equalize real ISO, shutter speed and DoF, then the uncropped D3X image should be better.

Now, my immediate problem is the choice of upgrade. Owning two competing camera systems, such as Nikon and Canon, must be a bit like having a split personality (I imagine).

I just checked Photozone to see their test results for the Nikkor 14-24/2.8 used with the 10mp Nikon D200, and Wow! This lens on the cropped Nikon DX format is sharper from corner to corner at 14mm and F2.8 than it is at F8. The results at F2.8 are about equal with F4 and F5.6, at 14mm. At longer focal lengths, performance at F2.8 drops a bit, but I wonder if anyone knows of a 21mm prime, designed for full frame, that's better than this, at F2.8, considering edge performance also.

http://www.photozone.de/nikon--nikkor-aps-c-lens-tests/361-nikkor-af-s-14-24mm-f28-g-ed-n-test-report--review?start=1

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Ray

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Re: Pentax K5 field review on its way?
« Reply #16 on: November 10, 2010, 01:34:24 am »

The fact that the K5 and the D7000 are sharing (I think), the same Sony sensor it's not surprising that they perform quite similar.
According to your comparaison with the 5D2, on the video session I did, there are differences. Visual differences. The 5D is a FF sensor and features 5MP more than the K5 and 9MP more that the camera involved. Differences are cristal clear in low-light and also the D.O.F you can obtain is more narrow with the 5D. In post-prod you would be much more limited with the K5 or the D7000. The D7000 seems to be an extremely good overall product. The 5D2 for stills has certainly much more to give for the money. We are talking about a 2000euros camera.
But if you already have Pentaxes lenses, the K5 is probably a very good choice. If not, I would probably stick in CaniKon

Fred,
I don't have any Pentax lenses. The Pentax Spotmatic was the first SLR I ever owned about 40 odd years ago, and I remember being thrilled by the through-the-lens experience and built-in light meter. It was a major technological breakthrough for me at the time.

The fact that you get the impression that the 5D2 video has better low-light performance than the D7000 is interesting. It conflicts with the DXO results, except in circumstance where you are using the maximum aperture of the lens.

For example, if I were using the Canon 24-15/F4 on the 5D2, and the Nikkor 24-120/F4 on the D7000, shooting the same dark scene at F4, but at different focal lengths to equalize FoV, then it's true the 5D2, at F4, would have a shallower DoF, and because of its slightly better 'low light' performance due to its larger sensor, should exhibit slightly less noise.

However, I question whether extremely shallow DoF is a desirable thing, especially when the subject is moving and the camera doesn't have auto-focussing in video mode, which I understand the 5D2 doesn't have.

I have enough trouble getting still scenes exactly in focus at wide apertures. Moving scenes could be a nightmare at F2.8 on full frame.

It's often been said that the only impartial, fair and sensible way to compare camera performance is at equal shutter speed and equal DoF. Do you not agree with this principle?

If your speciality is taking shots at F1.2 with FF DSLRs, then fair enough. There are no F0.7 lenses available for the cropped format to match that shallow DoF.

I suppose if you want to be really, really creative and get the tip of the subject's nose in focus, but the eyes out of focus (or vice versa), then the DoF advantages of FF are for you. No argument there.

But I suspect I will prefer to shoot video at less extreme apertures. I might prefer the 'less shallow' and less problematical DoF of F4 on a D7000 as opposed to F4 on the 5D2.

I know this is a lot of blah! blah! technical nonsense for you, Fred, but I really think you would benefit by understanding this issue.

On the DXOMark site, the 5D2 gets a higher ranking than the D7000 for low-light ISO (sports subjects).

This ranking clearly ignores the fair and impartial principle of 'equal shutter speed and equal ISO'. It assumes that for low light shooting you will automatically use the same aperture at the same ISO, irrespective of DoF consequences.

What happens if we equalize DoF and shutter speed by choosing a wider aperture for the D7000?

Well, we have to change ISO of course. The relationships become something like the following.

F4 at ISO 3200 on the D7000 produces the same DoF at the same shutter speed as F5.6 on the 5D2 at ISO 6400, assuming the ISO sensitivities are the same.

However, ISO sensitivities are not the same. The D7000 ISOs are more accurate. At any given 'manufacturer-nominated' ISO, the 5D2's real ISO is about 1/3rd of a stop lower than the 'real' D7000 ISO, which is also a bit on the low side. Example, ISO 3200 on the D7000 is actually ISO 2627, whereas ISO 3200 on the 5D2 is lower at ISO 2133.

Now I understand, Fred, at this point you are going out of your mind with boredom. That delicious chicken and pasta dinner with mushroom sauce you are planning is far more important.

But bear with me. The difference in DoF between the D7000 and the 5D2 is slightly more than a full stop, so, for equal ISO and equal shutter speed we should be comparing the the 5D2 at ISO 6400 with the D7000 at (say) ISO 4800, but this doesn't give us equal DoF. (Take an asprin at this point).


Because of the discrepancy in accuracy of ISO, between these two cameras, the differences in the ISO settings needs to be greater than one full stop, for equal ISO and equal shutter speed.

At such settings, the 5D2 would appear to have no image quality advantage, according to DXOmark results (except perhaps resolution according to lens quality and optimim aperture chosen). In fact, the D7000 is slightly better, but only at an extreme pixel-peeping level, so we can ignore that.

It's a pity that DXO do not test video quality. Trying to find any worthwhile comparisons between the D7000, 5D2 and 7D video output on the internet, is a nightmare. What a waste of time! Most video's I've seem so far are total crap, and none show a direct and meaningful comparison between the main contenders.

Perhaps after a couple of glasses (or more) of Jamieson's Run Chardonnay, it's me who is confused. If so, please set me straight. ;D


http://www.dxomark.com/index.php/eng/Camera-Sensor/Compare-sensors/(appareil1)/680%7C0/(appareil2)/483%7C0/(onglet)/0/(brand)/Nikon/(brand2)/Canon
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jac

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Re: Pentax K5 field review on its way?
« Reply #17 on: November 21, 2010, 08:11:50 am »

Hey people, doesn't anyone go into the field and take pictures anymore. When you get talking about the differences of one stop at ISOs far above anything possible a few years ago, I think you need to stop and take a reality check. Seems to me I actually got some pretty good images from my *istDs back in the ancient past. Get out and enjoy the light!
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Miserere

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Re: Pentax K5 field review on its way?
« Reply #18 on: November 22, 2010, 11:55:07 pm »

Hi,

A field review of the new Pentax K5 coming soon?

It seems that it is a much more exciting camera than the K7.

As I'm only interested in field reviews, and that this website is one of the very rare to offers field reviews by experienced photographers, (in opposition to the generalized tech bla bla)
I hope you will do the Pentax.

Cheers

Hi Fred,

I received a K-5 for review today and will be putting it through its paces over the next 3-4 weeks. I'm primarily a street shooter, but I'm sure you'll learn something anyway   ;)
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