bobn2

bobn2

Lives in United Kingdom Worcestershire, United Kingdom
Joined on Aug 28, 2007

Comments

Total: 71, showing: 1 – 20
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On article Nikon D7500 vs Canon EOS 80D (264 comments in total)

You say 'The D7500 is constructed with a combination of Carbon Fiber Reinforced Thermo Plastic (CFRTP) and magnesium alloy'. I don't believe that it has any magnesium alloy in it. On that basis the two cameras are equal, though the CFRTP is possibly stronger than the 80D's material.

Link | Posted on Jun 11, 2017 at 15:37 UTC as 55th comment | 1 reply

Looking at your overview video on the D750, I see a rather major error - you say that its chassis is mainly magnesium alloy. No, it isn't - it is Sereebo carbon loaded polymer in a monocoque construction (which technically means it doesn't have a chassis). It's the case than none of the DSLRs here, Canon or Nikon, has a magnesium alloy chassis, they are all polymer.

Link | Posted on May 20, 2017 at 15:19 UTC as 70th comment | 3 replies
On article Hasselblad X1D-50c First Impressions Review (316 comments in total)

If the GFX50S and X1D have the same sensors then they have the same ADCs, because it's a Sony Exmor design with the ADCs on the sensor. I'm wondering whether the innards of the two might not be very similar, and possibly also the lenses - the H cameras have a lot of Fulifilm in them and Hasselblad's lenses are Fujifilm.

Link | Posted on Apr 3, 2017 at 15:41 UTC as 84th comment | 6 replies
On article Throwback Thursday: the Canon EF 24-70mm F2.8L (116 comments in total)

Not actually 'constant aperture', rather 'constant f-number'. If the aperture was constant, the f-number would change as it zooms. Yup, I know it's pedantry, but it's that kind of misuse of 'aperture' that ends up with people not knowing what 'aperture' means.

Link | Posted on Feb 24, 2017 at 13:42 UTC as 8th comment | 2 replies

If too many photographers shoot the bride with a cannon it's going to put up professional liability insurance more than a little

Link | Posted on Dec 29, 2016 at 15:58 UTC as 127th comment | 2 replies

"The counterfeit EF 50mm lenses are made using electric circuits and parts on the interior, Canon warns, which fail to meet safety standards in multiple countries. "
I'm having some issues thinking of what might be the safety implications of these rogues circuits.

Link | Posted on Dec 19, 2016 at 17:52 UTC as 10th comment

OmniVision is American, not Chinese.

Link | Posted on Nov 23, 2016 at 21:28 UTC as 1st comment
On article 2017 Roundup: Interchangeable Lens Cameras $500-900 (552 comments in total)

"Uses the same 24MP sensor as its predecessor'. No, it doesn't. D3200 had Nikon 24MP sensor, D3300 has 2nd gen Sony 24MP sensor - they perform very differently and are a different size (old Nikon slightly sub-size for DX).

Link | Posted on May 10, 2016 at 15:45 UTC as 106th comment | 1 reply
In reply to:

Alex Permit: No E-mount. I suppose that's mostly because of the smaller installed base?

That's true, but the Batis is still a Tamron. Here is the Tamron patent for the Batis optical formula
http://www.lens-rumors.com/patent-of-tamron-85mm-f1-8-vc-lens-for-sony-fe/
and the Batis itself, same design
http://www.zeiss.co.uk/camera-lenses/en_gb/camera_lenses/batis/batis1885.html
That's the second time a Tamron patented optical formula has turned up in a Batis lens.
Presumably, the shorter lens register allows a simpler formula for the Batis.

Link | Posted on Feb 26, 2016 at 23:32 UTC
In reply to:

Alex Permit: No E-mount. I suppose that's mostly because of the smaller installed base?

Rather, I think that the E-mount version of this lens will be available as a Zeiss Batis. Zeiss have announced this with almost identical specifications, and we already know that the Batis range has close connections to Tamron.

Link | Posted on Feb 22, 2016 at 20:53 UTC
On article Nikon announces development of flagship D5 DSLR (442 comments in total)
In reply to:

falconeyes: Interesting.

The only reason I can figure out for such a desperate announcement is the Leica SL. Which must worry Nikon more than I thought.

Unfortunately, the announcement (giving a name, D5, and fact to become the next top-level again), confirms a sad thing: Nikon still does not innovate. If I had $7000 to spend for a next body, the SL suddenly looks rather tempting after this announcement ;)

I think this has more to do with the announcement sequence of the 1D X and D4. Canon pre-announced the 1D X by about 8 months, as I remember, leaving the D4 looking a little lacklustre, when it was announced just before it was available. In the end that made Canon looking a little desperate with such a long pre-announcement, but it worked to the extent it overshadowed the release of the D4. I think this is nikon's attempt to make a pre-announcement without making a pre-announcement. Presumably, Canon will soon announce the 1D XII, and Nikon is just saying to people - wait and see what we do with the D5.

Link | Posted on Nov 18, 2015 at 11:08 UTC

"Toshiba, who manufactured sensors for the Nikon D5200 and D7100" - and also the D7200. You've insisted it's a Sony, but you're wrong.

It's an interesting issue for Nikon, because Sony also bought the fab line on which the Nikon (D3, D3s, D3100, D3200, D4, D4s) sensors were made.

Link | Posted on Oct 26, 2015 at 12:02 UTC as 15th comment | 1 reply
On article Nikon D7200 Review (639 comments in total)

You're still saying this is a Sony sensor. I'm pretty sure it's a Toshiba like the D7100.

Link | Posted on Jun 4, 2015 at 19:49 UTC as 93rd comment | 3 replies
On article Sources of noise part two: Electronic Noise (237 comments in total)
In reply to:

Detail Man: Richard Butler and Rishi Sanyal:

These two articles about sources of image-noise are well presented and explained in your statements of clarification made in comments sections.

.

I like the way that DPReview writers appear to have the adopted the terminology "ISO-invariant" / "ISO-variant" in lieu of the (IMO, less descriptive) terms "ISO-less" / "ISO-full", and recall suggesting the alternate use of those particular terms in this post replying to "gollywop":

http://www.dpreview.com/forums/post/51241577

... when he was in the course of editing his to be published DPReview article here:

http://www.dpreview.com/articles/8148042898/exposure-vs-brightening

... and which he continued to use in his subsequent DPReview published article here:

http://www.dpreview.com/articles/6641165460/ettr-exposed

.

The more information regarding these subjects that is made accessible to readers within articles published on the DPReview site (in addition to appearing in forum posts), the better !

(continued) The term ISOless, was rather phrased in the sense 'you don't have to use the ISO control', and the speculative ISOless camera was a camera without an ISO control and a different style of UI based on explicit control of exposure. The application of 'ISOless' to existing cameras came from an observation that the D7000 was usable in an ISOless way (meaning 'ISOless was a methodology of exposure management, not a characteristic of a camera) So maybe the real term should be 'ISOless capable camera', signifying that point.

Link | Posted on May 14, 2015 at 21:03 UTC
On article Sources of noise part two: Electronic Noise (237 comments in total)
In reply to:

Detail Man: Richard Butler and Rishi Sanyal:

These two articles about sources of image-noise are well presented and explained in your statements of clarification made in comments sections.

.

I like the way that DPReview writers appear to have the adopted the terminology "ISO-invariant" / "ISO-variant" in lieu of the (IMO, less descriptive) terms "ISO-less" / "ISO-full", and recall suggesting the alternate use of those particular terms in this post replying to "gollywop":

http://www.dpreview.com/forums/post/51241577

... when he was in the course of editing his to be published DPReview article here:

http://www.dpreview.com/articles/8148042898/exposure-vs-brightening

... and which he continued to use in his subsequent DPReview published article here:

http://www.dpreview.com/articles/6641165460/ettr-exposed

.

The more information regarding these subjects that is made accessible to readers within articles published on the DPReview site (in addition to appearing in forum posts), the better !

As one of the people in at the beginning of the term 'ISO-less' I agree it's a bit clumsy. But I'd say that ISO-Invariant, as well as being equally clumsy is also fundamentally wrong. The question is, what is 'invariant', and it isn't ISO, since whatever you do, your final photo will have an 'ISO' (i.e. a relationship between exposure and 'density' or its digital analogue). In fact, in an 'ISOless' camera, what is invariant is the analogue gain, and the term 'ISO invariant' is really applying the confusion between ISO and gain which leads to many of the misunderstandings about ISO.

Link | Posted on May 14, 2015 at 21:03 UTC
In reply to:

dagobah: This is a nice article, thanks. We just had a discussion on this topic recently on the Pentax forum.

Sensor noise has definitely come down in the last few years -- I remember my Pentax K10D not being usable above ~ISO500. Whereas I am happy with the K-3 at ISO3200. That had to have been from the improvement of the electronic noise, no? Are there no more gains to be had on sensors of a specific size? If you're below the noise floor of shot noise, no improvement will be noticeable, and sensors wouldn't vary much in shadow noise performance.

What I've been thinking would be very useful when showing sensor performance measurements (such as DxOmark does) would be to have a curve for the sensor in question and a curve for and "ideal photon detector" of the same sensor size.

Another comment is that I am interested in ETTR -- could you maybe do a little practical guide addendum to this article at some point? Cheers.

I'm glad to hear of your unbelief in anything quantum. Presumably you abstain form using nuclear power, even from natural sources, like the sun.

Link | Posted on Apr 30, 2015 at 19:58 UTC
In reply to:

dagobah: This is a nice article, thanks. We just had a discussion on this topic recently on the Pentax forum.

Sensor noise has definitely come down in the last few years -- I remember my Pentax K10D not being usable above ~ISO500. Whereas I am happy with the K-3 at ISO3200. That had to have been from the improvement of the electronic noise, no? Are there no more gains to be had on sensors of a specific size? If you're below the noise floor of shot noise, no improvement will be noticeable, and sensors wouldn't vary much in shadow noise performance.

What I've been thinking would be very useful when showing sensor performance measurements (such as DxOmark does) would be to have a curve for the sensor in question and a curve for and "ideal photon detector" of the same sensor size.

Another comment is that I am interested in ETTR -- could you maybe do a little practical guide addendum to this article at some point? Cheers.

I think it's something slightly different. In the early days, CCDs had a higher intrinsic quantum efficiency that CMOS sensors. To compensate this, the earlier CMOS sensors (particularly the Canons and the D2X) used somewhat more transmissive and therefore less colour selective colour filter arrays than the contemporaneous CCD, thus establishing the tradition that CCD had purer colour. Now CMOS has reached and exceeded the intrinsic QE of CCD, but rather than restore the more selective CFA, the manufactures have gone after sensitivity and good low light performance, which they think is a bigger seller than pure colour. There have been cameras bucking this trend, for instance the D3X. The Canon 5Ds also is touted as having a more selective CFA, so might have more CCD-like colour.

Link | Posted on Apr 30, 2015 at 18:45 UTC
In reply to:

VidJa: does anyone know where we are in efficiency of the sensors? with other words, how many of the available photons do we measure with current sensors and how far can we expect to improve?

To martindpr (1 hour ago)
Nikon D2X 476%, mhm, yeah right... If 100% is max efficiency, then D2X must be inventing more of it according to the source you posted.
There are some anomalies in that data, down to failure of the function fitting methods. Different methods produce different anomalies. 476% is clearly wrong, it doesn't make them all wrong.

Link | Posted on Apr 29, 2015 at 09:06 UTC
On article Nikon D5500 Review (415 comments in total)

I'm interested by you comment on the lab test, p8. - '*We originally shot the scene with the Sigma 50mm f/1.4 Art as part of an attempt to introduce that lens as the standard across systems, but we ran into an issue whereby images from the D5500 were coming out noticeably noisier than the D5300. We found that at f/5.6 the native Nikon 50mm was giving consistent exposures shot-to-shot, while the Sigma was underexposing and yielding somewhat inconsistent exposures. Further testing is required and we'll keep looking into it.'.

Does that mean that the Sigma is not actually setting the f-stop that has been set?

Link | Posted on Apr 3, 2015 at 08:26 UTC as 79th comment | 2 replies

'EI is essentially the same as ISO.'
Rather, EI is the right term and 'ISO' is the wrong one. 'ISO' is an organisation with lots of standards, not all about photography. The Exposure Index (As defined in ISO 12232:2006), is the ISO standardised index we use to set exposure, rather than any other ISO standard. It would be pretty silly, for instance to use ISO 9, the standard for translation of Latin to Cyrillic characters, to set exposure.

Link | Posted on Feb 24, 2015 at 17:46 UTC as 16th comment | 1 reply
Total: 71, showing: 1 – 20
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