Following on from our look at the new correction parameters added into the latest DNG specifications, senior product manager and writer of Adobe’s Lightroom blog, Tom Hogarty, spoke to us about how these correction parameters were chosen and developed:

Adobe’s DNG specifications may seem like a rather esoteric and arcane document to go digging around in, if you’ve only got experience of developing pictures, rather than software. However, the latest changes, that allow for ‘corrections and enhancements’ might be of interest, because they give something of an insight into the kinds of processing and corrections that camera manufacturers are applying to their RAW data.

In order to provide a non-proprietary way of storing RAW data, DNG files have to include all the processing instructions necessary to produce a final image the way the camera manufacturer wanted. Consequently, to act as a universal format, the DNG specification has to have the capability to define all the different types of processing that those manufacturers might want to apply to their RAW data to accurately produce a finished image.

So the addition of correction and enhancement parameters (known as ‘opcodes’) into the DNG v1.3 specification gives us some clues about the behind-the-scenes work manufacturers are doing to produce the best possible images from the RAW data their cameras are capturing.

In all the excitement about smaller batteries and carbon-fibre effect hand grips, you may have missed the key message of the recent batch of camera announcements – that DSLR technology has reached a significant stage of maturity. The recently launched Olympus E-450 was without question the most subtle modification of an existing model we’ve ever seen and the new Sonys, with their revised styling and reworked user interfaces unquestionably have an awful lot in common with the preceding models.

Our discussion forums are a great resource for people looking to learn about photography, and it's therefore not surprising that certain topics are raised time after time. In many cases they are answered quickly and correctly, but certain topics are still subject to a great deal of confusion. One of these is the deceptively simple question of what the word 'standard' means in relation to lenses. It appears that there are certain misconceptions associated with this topic which reappear time after time, so in a bid to put the record straight, here's my attempt at an (almost) definitive answer.

There's something that's been troubling me a bit recently, and I want to get it off my chest. It's an irritation about the photographic equipment available today, and its fitness for the purpose for which it's most likely to be used. It has germinated over the course of testing an array of 50mm prime lenses, developed further with the recent arrival at the dpreview offices of an array of new fast primes, and finally crystallized with the relative lack of interesting new products and ideas at PMA. And it's this; most manufacturers seem be be thinking very conservatively, treating digital as though nothing's changed from the days of 35mm film, and simply aren't making the right lenses for photographers today.

In the Dynamic Range section of our DSLR reviews we usually look at something that we call ‘RAW headroom’. The RAW headroom could probably be described as the highlight and shadow detail that has been captured in the RAW data but gets lost when a camera’s internal software applies a tone-curve to the RAW image data.

As a rule cameras apply a typical 'S' shaped tone curve to JPEGs to give a visually appealing contrast without harsh clipping of the brightest or darkest tones (the 'shoulders' of the S curve provide a more gentle roll-off than a straight line would). The tone curve applied is often quite steep, sacrificing the tones at the the extremes of highlight and shadow in the pursuit of 'punchy', consumer-friendly out-of-camera results. At the shadow end this is rarely a problem (the very darkest tones are mapped to black, which isn't visually unpleasant and helps reduce noise), but at the highlight end it can mean that what should be a very pale blue sky turns white, or that highlights have harsh edges instead of a gentle gradient. There's no way to get back detail that the camera's tone curve left out of a JPEG, but it is possible to tweak more out of a raw file. Having access to the sensor's full dynamic range also means that you can fix mild under or over exposure by reaching into the headroom.

And so it's very useful to understand what raw headroom is and how you can make use of it to get the maximum out of your images. We regularly receive questions regarding this particular section of our reviews via our feedback system and in the forums, so I thought it would be a good idea to provide some detail about the dpreview approach to raw headroom in a blog article. This isn't a deeply technical post; it's more of a primer on what we do, and why you need to know about the dynamic range hidden away in your raw files.

As well as the technological side of the Challenges system - which my colleague Jaysen has blogged about elsewhere - the beta development phase is giving us a useful insight into the way users are likely to behave and what their expectations are.

It's long been obvious that the existing dpr review format - even in its seriously truncated 'concise' form - is unsuitable for the majority of what can be broadly termed 'point and shoot' compact cameras, and I've been wanting to develop a group test format for some time now. There are simply too many compact cameras released each year for us to keep up with (even the most basic camera takes a minimum of a week to put through our battery of tests and to produce a gallery), and the truth is that image quality amongst competing models doesn't - for the most part - vary that much. But there are always going to be exceptions, cameras with image quality that falls well below or rises way above the mean, and unless we test a far higher proportion of the models on the market there's a risk we'll miss these occasional stars and lemons. The group test format may not give you as much detail about the individual cameras, but it does give you a much better idea of the relative quality of a far greater number of competing models.

Ten years, nobody who starts a web site can honestly claim to have an accurate vision of what that site will be like ten years down the line.  When I wrote my first digital camera article and dropped it onto the now defunct photo.askey.net URL I had no intentions for it to be anything more than an opinion piece of my purchase. But then a funny thing happened, I began getting emails, lots of them, all asking about my article and what I thought of other cameras.  It seemed that this "digital camera thing" was becoming popular and what people were looking for was a site which was always up to date and could deliver honest, detailed reviews.  I went out on a limb and spoke to several manufactures, to my surprise the majority were extremely receptive and before I knew what was happening I had a steady flow of cameras coming my way.  Over the next couple of years I developed the primary site features (camera database, forums, news, etc.) as well as gradually improving the testing methodology (but at all times trying to be consistent).

In my last blog post, I rambled on about the challenges rendered by, and insight that comes from, having to become familiar with the interfaces and operating systems of all the different manufacturers.

It's a learning process that makes you realise that, while some are more awkward than others, most of them are in need of some work. Without question, all the current DSLR user interfaces (particularly the menu structures), are struggling under the weight of all the additional features that have been introduced. And it's not just DSLRs - I’ve spent this week working with a compact that requires nine button presses to change exposure compensation. I don't envy the task of trying to sensibly prioritise and structure so many features in a menu system, but I wonder whether it couldn't be done better...

Hot on the heels of publishing a new lens review (the Tamron 18-270mm F3.5-6.3 VC), I thought our readers might be interested in getting an insight into the overall review process and the amount of work involved. While some of our more naive forum posters appear to labour under the misapprehension that our reviews are just a few days work conducted entirely in the studio, the reality is that the process is a lot more complicated than that. In fact the experience gained from going out and actually using the product is also very important, and informs the final conclusion just as much as all of that studio work. So in a nutshell, here is what the review process actually involves.

There has been much contention recently that we're being unfair on high megapixel cameras which show higher levels of noise than lower megapixel cameras. The almost universal argument is that "you can downsample the high megapixel image to reduce noise". This statement is often made with no evidence or example, this article is intended to provide some examples so that you can make your own mind up.

Starting work at dpreview.com is an odd affair. Not only does writing for the web entail many more people reading your work (and scrutinising and criticising it), it also means learning to write for a very different audience: an International one...

The responses to my list of upcoming lens reviews were certainly interesting, and proved (as if we didn't already know) that you can't please all the people all the time. Indeed with requests flooding in (OK, trickling) for reviews of everything from ultrawides to superteles, via F2.8 standard zooms and fast portrait primes, it seems that in this particular field we can only please a few people at any one time. We've also had a few comments on the 50mm lens review series (some encouragingly along the lines of 'why bother?') so I thought I'd expand a bit on our reasons for testing these lenses.

One of the strangest comments I repeatedly see is: ‘they don’t use their cameras in the real world,’ stated, as all things must be on the forums, as absolute fact. As if the sample galleries that accompany every review somehow generate themselves.

As my friends (who can no longer meet up with me without having a camera pointed at them or being asked to stand around as I kneel, climb or wait to ‘get the shot right’) will testify, we all-but sleep with the camera we’re reviewing (and I can’t guarantee some of us wouldn’t do that, if we it weren’t for the fact that the results would be unpublishable). And part of the opinion we build up about a camera is based on that real-world experience, rather than simply shooting test charts all day – though it’s possible to anticipate a lot of the real-world image performance from learning to interpret the different tests.

We try to make sure that our shooting experiences are a little bit varied – or, at least, that’s the justification I used to convince Phil to let me attend the first round of the Track Cycling World Cup in Manchester, recently. I’d originally been hoping to take the EOS 50D and a nice, fast telephoto lens; perhaps with an external flashgun of some description. Unfortunately, my all-too-efficient colleague Lars finished and published the review before the day came.

As I sat working my way through my emails this morning it occurred to me that it might be worth posting a quick note about the best way to contact us here at dpreview, what's likely to get you a reply and what happens when you send feedback.

Firstly, and surprisingly for some of you I'm sure, we don't only welcome your feedback, we do read it and we often act on it. What's important to remember here is that our editorial team here consists of a handful of people with full-time jobs producing content (as well as forum moderation), and this means that we simply can't answer every email we get, nor can we acknowledge every bit of feedback. But that doesn't mean it hasn't been read (and if necessary, acted upon).

From the bet-you-didnt-see-that-coming dept., your eyes don't deceive you, we've really started a blog. To be more accurate, two blogs, one for our editorial team and one for our developers. Over the last few years we've come under criticism for not being more open with our readership, there have been many reasons for this, not least of which a simple lack of resource.

The good news is that we now have a team, and a good one at that, six on the editorial team, two developers and often floating (bouncing?) between the two, my good self. So here's a channel for us for be more open with you, to try to keep you up to date with what's going on behind the scenes and as a place for us to answer common or topical questions in a more permanent / easily referable manner.

So dig in and enjoy, we've primed the blog(s) with some news and I'll be cracking the whip to ensure we have a steady flow of entries here.

Around a year ago we had our new reviewers trained to the point where they were ready to produce their own reviews. Before we even started recruiting we knew we'd start them off with compact cameras - partly because a compact camera review is considerably less involved than an SLR, partly because there are so many compact cameras on the market. Perhaps predictably every compact review we released was met with a torrent of complaints suggesting that we shouldn't be wasting time on 'point and shoots' when there were so many SLRs in the queue.

By the time spring arrived two things were obvious; that we were going to struggle to keep up with the flood of new SLRs, and that the compact camera market had reached something of a plateau, with 'new' models being nothing more than 'old' models with marginally bigger screens or vital new features such as smile detection. So we took the decision (and, I should add, not lightly) to concentrate our limited resources on covering all the SLRs in depth before we went back to compacts.

To be honest it wasn't that difficult a decision; we get at least 20x more people reading an SLR review than a compact review (with most compacts sold being in the sub-$150 bracket I think it's safe to assume that the amount of pre-purchase research buyers are doing isn't considerable).

We’ve been, from time-to-time, accused of using overly flowery language in the reviews on this site. We try to tread that fine line between trying not to say exactly the same thing time-after-time and lapsing into the incomprehensible. And, on the whole, I think we get it about right. But, as you'd expect, there is the occasional dissenting voice on the forum demanding that we must just state the facts as dryly as possible (But then the forums would be a much less 'vibrant' place if everyone agreed on everything).

However, our linguistic forays - even at their most florid - are nothing compared to the adventures in prose undertaken on behalf of some of the camera companies. Perhaps it’s because much of the underlying material has been translated from unrelated languages – a process that can result in some beautiful, if somewhat enigmatic, imagery. Or maybe because there are few jobs more thankless than having to compose three pages-worth of compelling text about a camera that differs from its predecessor only in the inclusion of a larger screen, a more densely-packed sensor and a smattering of new scene modes (surely soon to include ‘Friends eating Lancashire Hotpot on a Wednesday evening in summer' mode).

Statements such as: “The subject floats serenely in its own world, like a misty memory or the landscape of a dream” are not unheard of, making me slightly concerned that the next time I order prints I’m going to be confronted with the question: ‘What finish would you like? Gloss, Matte or Whimsy?’

My favourite of late, however, must be the press release that suggesting that the camera it was pushing included a mode that can create: “a sense of déjà vu.” Which sounds lovely, unless you make the mistake of thinking about it too hard. I suspect that, if you take photos for yourself, then you’re probably doing so to preserve memories, in which case the sensation of having experienced the scene before should really come as standard; and those who’re taking photos to show or sell to other people probably aren’t hoping for the response: “I’ve already seen this.”

We have a brand new blog which desperately needs some content before it can be launched and following our recent Canon EOS 50D review there has been quite a lot of discussion in the forums about the use of Adobe ACR as a RAW converter in our reviews. These, I thought, were two good reasons to get into blogging mode and write a brief article that explains why Dpreview is using ACR and not proprietary or other third party converters for its tests.

The level of interest in our Canon 18-200mm review has persuaded us that we should test a few more superzooms in comparison  (the great strength of the widget is that we don't need to have the lenses in-house simultaneously for side-by-side shooting). So expect to see some leading 18-2x0 mm zooms interspersed with our still-ongoing series of 50mm primes. Lenses on the shortlist for reviews in the near future include the following:

50mm Lenses:

• Pentax 50mm F1.4 (on K20D)
• Sony/Minolta 50mm F1.4 (on FF and APS-C)
• Canon 50mm F1.8 II
• Nikon 50mm F1.8

Superzooms:

• Sigma 18-200mm OS
• Tamron 18-270mm VC
• Sony/Pentax/Tamron 18-250mm

(The Panasonic/Leica 14-150mm would be an obvious comparison for Four Thirds users, but its limited availability and high price will necessarily affect the final decision on whether we review it.)

At some point we still hope to test the Sony 70-200mm F2.8G on both FF and APS-C, to see if it can justify its stratospheric price-tag in comparison to the competition from Tamron and Sigma.