Category Archives: Photo Technology

Technical aspects of photography.

DxOMark @ 251 cameras

test

DxOMark Sensor scores for 251 cameras (click to view larger)

Here is another update about new cameras tested by www.dxomark.com. The test only looks at the noise and dynamic range peformance of cameras – it doesn’t cover resolution, speed, ease-of-use, durability, etc.

Since my previous posting, 5 new cameras have been tested by DxO Labs. Modern cameras span a range of over 60 points. A 3 point difference is barely visible to specialists, 10 points is readily visible, 30 points tends to be obvious even when someone is not paying attention to image quality at all:

  • Sony A3000/A5000 (78 and 79 points).
    The pricing of APS-C system cameras with a state-of-the-art sensor has dropped below US$ 500 with the introduction of the Sony A3000 and A5000. Despite the Alpha branding, these are basically NEX models (Sony has dropped the usage of the NEX brand). They thus have E lens mount (as used in the NEX series) rather than the A-mount (as used in the Alpha 77).
  • Leica S medium format (76 points).
    The Leica S medium format camera, despite its $28,000 price,  does not really have a state-of-the-art sensor. It “still” uses a CCD sensor technology, although  recently medium format models with a Sony-built CMOS sensor have been recently announced (by Hasselblad, Phase One and Pentax). CMOS sensors should manage to make medium format cameras more all-round cameras again. Arguably, because medium format cameras are often used in studios or tripods, they historically had more emphasis on resolution, color fidelity and lens quality than on low light or high dynamic range.
  • Leica X Vario (78 points).
    Leica also gives you the option of buying the X Vario which actually performs similarly to the Sony A3000 or A5000, but at a Leica price.
  • Olympus Stylus 1 (51 points).
    The Olympus Stylus 1 scores surprisingly low for a new camera with its SLR-like looks. But looks are misleading here. If you look carefully at the specs, it turns out to have a very small sensor with a 4.66x crop factor. This puts in in the same league as the Canon Powershot S120. The Stylus 1 (51 points) is outperformed by the more compact S120 (56 points).
Canon Powershot S120 next to the Olympus Stylus 1 (www.camerasize.com)

Canon Powershot S120 and the Olympus Stylus 1 have the same sensor size (www.camerasize.com)

DxOMark @ 246 cameras

DxOMark Sensor scores for 246 cameras (click to view larger)

DxOMark Sensor scores for 246 cameras (click to view larger)

See http://peter.vdhamer.com/dxomark_nov13/ for the previous snapshot and some explanatory text.

In this January update, ten new cameras and four extra labels were added. Sorted on descending price, these are:

    • Sony A7 (a 24 MPixel full-frame mirrorless camera)
    • Sony DSC-RX10 (performs like Sony’s two RX100 models)
    • Sony NEX 5T (likely the last NEX-branded model)
    • Sony A3000 (great image quality at low cost)

Note that all four happen to be Sony. I add labels in the (a) graph  to cameras that are notable from a technical perspective, and to the (b) graph when they have an interesting price for their performance level.

Although not tested yet, it will be very interesting to see how the two medium format backs perform with Sony’s new 50 MPixel sensor. They might becoming the new record holder (although the Phase One IQ250 doesn’t allow you to shoot about 6400 ISO).

 

State of the DxOMark (camera nerdiness)

DxOMark scores as of Nov 2013 (click to view larger).

I updated my overview chart with available high-end cameras. See http://www.dxomark.com/Cameras/Camera-Sensor-Database for detailed benchmark results for specific cameras. As usual, there is a lot of interesting information in such an overview:

  • Assuming you care about low light and high dynamic range performance, the best cameras have full-frame sensors (the blue dots). You knew that – right? Well, surprisingly full-frame sensors beat even larger (purple, pink, red) sensors. So don’t bother spending big money on a medium format camera unless you really need the super-high resolution. Or need it show that your equipment is clearly on a price class of its own.
  • The so-called APS-C cameras with 1.5x or 1.6x sensors have improved. Examples: the Nikon D5200 and D5300.
  • The Sony NEX-5R mirrorless (which is 1.5x) has a slightly higher price than an APS-C SLR, but the body is smaller and the performance is competitive. Mirrorless models should have the same performance as an SLR with a comparable sensor. A mirror doesn’t add image quality – it just makes a click sound like ke-lick.
  • Canon still has a long way to go to catch up with its APS-C sensors (1.6x). The Canon 70D performs slightly better than the old Canon 7D, but a comparison to Nikon or Sony tends to be embarrassing.
  • Recent Micro Four Thirds cameras (Olympus & Panasonic) have improved and are even ahead of Canon’s APS-C (1.6x) models.
  • The Sony RX100 and RX100-II are still doing fine – at least considering their small sensor size (2.7x or 1/1″ ). The Nikon Series 1 is technically not state-of-the art, but nice if you like white or pink gear: it targets a young Asian lifestyle market.
  • The premium pocket cameras have improved. Especially the 1/1.7″ sensor models such as the Canon Powershot S120 and G16 and their Nikon equivalents.
  • The best deals if you need a high quality model can be found at the top edge of the cloud in diagram “b”: you get the highest quality in that price range. Note that the prices shown are official prices at introduction, and will differ from current street prices. These deals include:
    • The Nikon D600 and D610. These are essentially the same camera, but the D610 resolves a dust issue.
    • The new Sony A7R mirrorless. Note that this model uses Sony E-mount lenses, but actually requires new Sony full-frame E-mount lenses called “FE”. So it will take a while until there are enough lens options.
    • The Sony RX1 and RX1R. These look overpriced (and probably are – although I ordered one myself), but their price does include an excellent 35mm Zeiss f/2.0 lens. On the other hand, they do not come with an optical or electronic viewfinder. These cost about 500 US $ or Euro extra. Lens hood pricing is  joke (so look into the Photodiox accessories).
    • The Nikon D5200 or D5300. Both have a 24 MPixels state-of-the-art sensor, but the newer one gives sharper images (no AA filter) if your lenses are up to the challenge.
    • The Nikon D3200. Also 24 MPixels with state-of-the-art sensor technology.
    • The Pentax K50 and K500. A somewhat overlooked brand.
    • The Nikon Coolpix P330. A “take me everywhere” camera at a lower price point than the excellent Nikon Coolpix A or FujiFilm’s X-100s models.

Note that some major new camera models are not shown because DxO Labs simply hasn’t tested them yet. These include:

  1. The new full-frame Nikon Df (with the professional Nikon D4′s 16 Mpixel sensor). It should score about 89 (D4) for $3000 – nice, but not sensational unless you insist on a retro look and feel.
  2. Most FujiFilm X-Trans models have not been tested. Tests may be delayed because they have a non-standard color filter array (complicating raw conversion). The CFA design allows the sensor to work without a low pass filter. Alternatively, the missing tests may be because FujiFilm is not enthusiastic about their cameras’ DxOMark scores (pure speculation on my part, but the FujiFilm X-100 didn’t score exceptionally well).  FujiFilm high-end cameras are getting a lot of attention from serious photographers who prefer small, unobtrusive cameras with a classic mechanical feel.
  3. The Sony A7. Many people wouldn’t really benefit from 36 MPixels (Sony A7R) without an image stabilizer or a tripod or high-end lenses.

For a detailed explanation of what the benchmark itself means, see http://www.luminous-landscape.com/essays/dxomark_sensor_for_benchmarking_cameras2.shtml. Note that the number of tested cameras has meanwhile increased from 183 to 236 models.

 

Lightroom 5

Lightroom 5 was released on June 9th 2013. It is a modest upgrade to Adobe’s main software package for photographers. The limited number of changes may be because it took 1 year to develop (Lightroom 4, by comparison, took 2.5 years). A new version of Lightroom may have been needed to get a clean baseline of tools that coincided with the release of Adobe Creative Cloud.

Software aspects

The new version still contain “encounterable” minor software bugs. Although these seem mainly related to the user interface, less eager adopters may want to wait for a 5.1 upgrade.

A Lightroom 5 bug
The above error appears to have popped up in Lightroom versions as long ago as 2008. But I hadn’t seen worthwhile errors in earlier Lightroom versions, so maybe LR5 was brought to the market somewhat rushed.

Lightroom 5 incidentally requires Windows 7 or 8. Windows Vista (which I still run on my laptop) is no longer supported.

The Lightroom concept

Despite its official name

Adobe® Photoshop® Lightroom® 5.0

Lightroom does not create modified image files from original files like Photoshop does. Instead it stores the adjustments you used to modify the image (e.g. “crop the image”) on disk. This is done in a so-called catalog. It automatically re-applies these adjustments whenever you view, print, edit or export the image. This saves storage space, simplifies file management and is convenient if you afterwards change your mind about any of the settings (e.g. “make the crop larger”).

From Photoshop to Lightroom

In general, Lightroom is meant for photographers who want to post-process their images, while Photoshop is nowadays mainly for graphics professionals who want to create new images. Sometimes a photographer does need Photoshop, but usually Lightroom is easier and faster to use because it is designed for photographers.

In each new Lightroom release the needs for Photoshop decreases a bit. The new licensing model for Photoshop may further accelerate the migration of photographers to Lightroom: you can still buy Lightroom, but you need to pay a yearly fee to use Photoshop (and a bunch of other Adobe tools).

Main new features in Lightroom 5

Radial gradient – This is a way to adjust a circular or elliptic area with soft edges in a number of ways. It is comparable to “dodge and burn” in the darkroom days.

rabbit_gradient

Circular gradient used to add fill light, color temperature and clarity.

Previous Lightroom versions had a few tools that are somewhat comparable:

  • Graduated Filter – for modifying one end of the image. Straight.
  • Adjustment Brush – for modifying an area which you paint in with a brush. Flexible.
  • Post-crop vignetting – light/dark adjustments only. Always in the middle of the crop.

Smart previews – These are essentially about 4 MPixels versions of the images that can be used if the full images are temporarily not available. You can choose which images or directories have smart previews. The software uses available smart previews if the USB drive or (in my case) NAS containing the images is not online. If you have access to smart previews, you can edit the images just like you could edit your original image – although you cannot see the image at full resolution. In my case that would mean editing at max 2540 × 1693 resolution without being able to zoom in to see the full 21 Mpixel resolution of my Canon 5D2. The feature is useful for laptop use, but also has benefits if you need to send somebody a Lightroom catalog to view or even edit.

Smart Preview2

Smart Preview controls are below the histogram.

Smart Preview

Smart previews are internally 2540 pixel raw files in Adobe’s DNG raw format.

Straightening – The “Upright” feature corrects tilted horizons and fixes problems with perspectives in architectural photography. Unlike DxO’s Viewpoint, you don’t have to indicate a set of lines or a rectangle that are supposed to be straightened. The software detects this automatically and gives a few options within the Lens Corrections section. Note that the image is warped to get this result.

Original image

Original image

2013_Vienna_09-2

Automatically straightened

Fully straightened (automatically)

Fully straightened (automatically)

Note that there are parts missing parts in the final image. These would normally be shown in black and cropped off by the user.

You could argue that this feature is the poor man’s Tilt and Shift lens: with a camera on a level tripod a wide-angle lens should get you similar results. The wide-angle should be enough if you keep the camera level, but shifting the lens up can get the horizon below the middle of the photo if required. This was not required for the above photo.

Other new features

PNG file support – I have some PNG files in my archive that I used for creating photo books. “Synchronizing” my storage folders using Lightroom 5 now brings these files into Lightroom. The files are not too relevant as the format is seldom used for photos, but here is an example of a PNG file that I used as an illustration in a photo book:

Continuous_happinessSpot removal – Lightroom 4′s circular spot removal tool has been extended to allow you to paint away any bobs that needs replacements.

In addition, a tool is provided to make sensor dust spots show up better. Here is part of the original image before any corrections. If you look carefully while slowly scrolling the image you may discover several dust spots:

Original image (with spots)

Original image (with spots)

While using the Spot Removal (Q) tool you can enable Visualize Spots mode. This enhances edges and shows them as white pixels. Black pixels represent lack of local detail. The ten or so small circles in the sky are dust spots:

Spots highlighted by Lightroom 5

Spots highlighted by Lightroom 5

The next screenshot shows eleven spots that I had manually discovered (using Lightroom 4) and had fixed earlier. In this case, you can see that I had manually discovered (using my motion trick at 100% magnification and slightly increased contrast) pretty much the same spots that Lightroom 5 could capture. Note that finding spots in a cloudless blue sky would be easier.

Spots repair locations

Spots repair locations

 

DxOMark Camera Sensor article (v2.0 and v2.0.1)

I have been working on an update to my original DxOMark article. That update has just been published on Luminous Landscape, a well-known photography site operated by the Canadian landscape photographer and publicist Michael Reichmann.

A slightly newer version of the article is available at the DxOMark website. It features four extra cameras and almost identical text.

Sample DxOMark results

The article covers various aspects of image sensor size and its impact on image quality. The article is built around original benchmark data measured by DxO Labs. I have rehashed their data (with permission) to stress basic trends and highlight a few topics:

  • Benchmark data for over 180 high-end cameras (starting at about $400).
  • Which benchmark numbers by www.dxomark.com are most relevant for your needs?
  • The technical relationships between sensor noise, dynamic range and resolution.
  • A comparison of what noise does at low ISO and at high ISO (this is trickier than “doubling the ISO reduces the signal-to-noise ratio by 2×”).
  • The implications of using “mirrorless” cameras (and associated smaller sensors) on image quality.
  • The image quality of the new wave of cameras that use Sony’s new Exmor sensor with its excellent low ISO dynamic range performance. With a bit of speculation of whether Canon (that normally doesn’t use Sony sensors) can catch up with Nikon (that does regularly use Sony sensors).

You can contact me about the article via comments on this website. I will also try to keep an eye on comments on the LuLa and the DxOMark fora (forums).

Magic Lantern for the Canon 5D Mark II

What is Magic Lantern?

If you own a Canon 600D, a Canon 60D, Canon 5D Mark II, or certain of their predecessors, you might be interested to hear that you can extend the capabilities of your camera for free (although a donation is requested). This is not by replacing the camera’s internal software by a newer version (recommended, but this mainly fixes bugs), but by adding software from a bunch of non-Canon developers. This Magic Lantern software extends the existing Canon software with many new features that target technically inclined videographers and photographers.

Features for photographers

Magic Lantern was originally created mainly for those who use Canon DSLRs for serious video work. I don’t know much about video, so I will only describe features that help photographers.

The features are somehow largely centered around Liveview and likely benefit photographers most who sometimes need to do “slow” photography: they use a tripod, use tethering in a studio to check focus, have a complex setup or simply want to have maximum control. Having said that, Magic Lantern states that it has benefits as well for photographers that are in a constant hurry: it gives you the option of putting certain options that you use a lot under a particular button.

A few of the key features:

  • focus peaking – whereby the Liveview image displays which parts of the image are in focus. Useful when you want to carefully control what is in focus. This can be seen as an alternative to tethering your camera to a computer via USB in the studio.
  • exposure clipping – the Liveview image can show which parts of the image will be too light and too dark using overlaid zebra stripe patterns.
  • more on-screen data – for example the current main camera mode (e.g. M), focal length and focus distance.
  • focus loupe – you can see part of the image zoomed in 2x or 3x to check sharpness. This feature is fancier that Canon’s counterpart and can even simulate what a split screen focus aid used to look like.
  • interval timer – you can take 100 pictures at 60 second intervals to show a flower opening. Or 1000 pictures at 1 hour intervals of a construction site – all providing you can get your battery to last.
  • triggering exposures – the shutter can automatically fire if the scene brightness or content changes significantly. Essentially a makeshift motion sensor.
  • automatic HDR – not only can the camera take a series of images at different exposures automatically, but it can take the entire series at one press of the button. It can even determine how many exposures are required automatically (or manually) and give you a rough preview of the merged image. Pretty cool. Essentially this gives your 5D2 a feature found in the 5D3, but without the artsy options: you do your real HDR merging afterwards on a computer.
  • improved mirror lockup – flip up the mirror a few seconds before taking the picture to reduce vibrations. The Canon equivalent is relatively tedious to operate.

Display when shooting video using Magic Lantern

The actual list of features is about as long as the list of features that your camera originally came with. So some people only use 2 or 3 of the new features. Others actually do read the software manual and experiment around (takes an evening – just like Canon’s firmware).

Installation and risk

There are risks involved in tinkering with complex equipment. My feeling is that the risk is comparable to opening up PCs to upgrade memory. If you never did something similar, you can get someone else to install Magic Lanterns (ML) and show you the basics.

The risk is lower than you might expect because ML doesn’t simply overwrite Canon’s software: it runs as an add-on and (in most cases) you will not see changes to the menus provided by Canon. There is a simple procedure to uninstall ML entirely.

This is essentially how ML works under the hood:

  1. A minor modification to Canon’s software makes the camera Magic Lantern aware. Comparable to a boot loader on a PC. ML is incidentally not the only party that does this (there seems to be a USB remote controller that uses the same trick to extend Canon’s software).
  2. Whenever you activate the camera, the firmware first checks for the presence of special non-image files on your flash card. If found, it loads Magic Lantern from the flash card. This does not visibibly delay camera operation. The ML software sits alongside the Canon software in camera memory (RAM). If the ML files are not found on the flash card (or you hold  down a button while turning it on), Magic Lantern is not loaded and you get  unmodified camera behavior. Alternatively, you can choose to carry memory cards with and without ML.
  3. Running ML,
    • the optical viewfinder information display is unchanged
    • the LCD viewfinder for LiveView displays significantly different information
    • Canon’s own menus (Menu button) are for 99% unchanged
    • you can view ML’s own menus by pressing the Erase button while in Liveview mode
  4. Whenever you make changes to ML settings this is written to the flash card for the next session. Some changes are also stored in the camera’s non-volatile memory (e.g. when ML menu’s interact with existing Canon features?)
  5. The ML files stay on the flash card, even if you erase the card using the camera. Actually ML formats the card and then writes the ML files back from memory. If you erase or format the card entirely using a PC, you need to reinstall the ML files onto the card. Until then, you will be operating without ML when you use that card.

Quality and stability

I cannot give you hard numbers, but since version 2.3 the stability seems to be close to that of Canon’s own software. Both have occasional bugs and both try to fix these bugs as soon as possible. ML is an open source project, so anyone with (considerable) programming skills can contribute.

All this doesn’t mean you can never run into a problem: ML software adds complexity to the entire setup, and strange combinations of features may give strange results. But if you stick to mainstream usage of the features (= use them more or less as documented) you should be alright.

Some features are clearly marked as “for very advanced users”. One example is the ability to take pictures in a low-res format while in Liveview mode without any shutter motion or sound whatsoever. A bit weird, and it actually seems to work, but you won’t be using this unless you are a video technician or are motivated enough to figure out how to deal with these “422″ encoded frames.

A final example is a menu item called “Don’t press this”. The user manual just says not to press it. Actually it probably doesn’t do any harm (otherwise why give it such a tempting name), but I don’t want to press it just yet. I suspect it contains a game that is totally not camera related. After all, your camera is just a computer with an industrial strength webcam attached as a peripheral (at least that is how geeks tend to see it).

Drawbacks

So far, things are going well with my own use. And ML has thousands of heavy users who rely on it on a daily basis. The documentation is actually pretty good – including the description of the risks involved. But…

  • It will only install on the latest version of Canon’s firmware. So you need to upgrade a 5D2 to v2.12 before you can install ML. A sensible choice by ML to minimize risk.
  • Running ML will slightly increase battery drain. Essentially because it gives the ARM processor more work to do because of extra features. It will increase batter drain a lot if you start using Liveview more than you previously did.
  • ML increases overall system complexity somewhat: it is like upgrading from a 5D Mark II to a 5D Mark III – more features which you may or may not use.
  • ML is not available on all currently Canon cameras (notably not the 7D or 5D Mark III so far). ML is written by volunteers and all this is a lot of work.
  • Something could go wrong. But the manual explains how to get the camera up and running again in the more common cases. As far as I can tell, the risk of loosing images stored on the flash card is absent, but there is a risk that you may need to briefly remove the batter to recover. A quote from the Magic Lantern FAQ:

In practice, we are doing our best to prevent these situations, and thousands of users are enjoying it without problems. However, this does not represent a guarantee – use it at your own risk.