SJ5000+ Optimum Exposure Setting

Like all small sensor cameras the SJ5000+ has limited dynamic range. Out of the box it tends to blow out highlights resulting in white skies and strange colour casts. I shot some test dashcam video with exposure set to -1.0EV The sky looks pretty good but bright buildings are still blowing out. Other settings were 1080 60P and AWB, no post production adjustments were made. Even underexposed the level of shadow detail looks pretty good and could be boosted in post. I will test at -2.0EV and see if that improves things though I expect some Photoshop work will be required to bring up mid tones and shadows.

Summing up, video is pretty good here and I reckon that better is possible yet.

The Youtube link posted below doesn't do justice to the original which looks much better.

 

 

SJCAM SJ5000+ Firmware Wishlist

There is no doubt that the SJ5000+ is a work in progress and SJCAM may now be regretting their rush to get to market before the 2014 holiday season as the bad feedback from early adopters must be harming their reputation. Unfortunately much of far eastern culture and business relationships is about saving face and it would be a shame if this got in the way of squaring up to any shortcomings which have come to light.

May I suggest that SJCAM need to first address some existing issues:

1. Crashes and freezes.
2. Power management.
3. WiFi stability. (If this is hardware related then offer a rebate or recall)
4. Waterproof case obstructing corners of still images in 4x3 aspect ratio.

When these problems are solved SJCAM could retrieve some kudos from retrospectively adding some new features to the camera.

1. Control over sharpening. Offer a zero sharpening option especially in stills.
2. Auto Shooting. more interval options to allow production of 4K Super High Definition time lapse, 1/2sec, 1sec, possibly some longer than 60sec.
3. Zoom option which crops video image "on chip". That is uses a reduced area of the image sensor and real pixels rather than cropping the video output and uprezzing which exaggerates noise and sharpening artefacts and smears detail.

Finally a suggestion for a model option, (SJ5050?), with a narrower field of view and less fisheye distortion.

SJCAM SJ5000+ and 4K Video

SJ5000+ owners who can't (or won't) afford a GoPro Hero4 and want to experience the joys of Ultra High Definition 4K Video can take advantage of the Auto Shooting function to assemble time lapse videos in 4k. This is not to be confused with the built in time lapse facility which processes in camera to output standard High Definition video. The individual 16 Megapixel frames must be imported into the video editor of your choice and assembled into footage. Not difficult, I use Photoshop, any version after PS6 will do it. There are advantages in using this method to create time lapses at lower definitions also. Provided that intervals of 3secs or greater are OK, (built in time lapse goes down to 1sec), having 16 Megapixels to play with gives you the opportunity to do zooms and pans to liven up otherwise static scenes without losing detail, likewise a fair level of de-fishing can be achieved keeping full HD resolution.HERE >
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SJ5000+ Still Image Quality

On paper the new SJ5000 models promise a big jump in quality over the previous SJCAM model, the SJ4000, which boasted of 12 MP still images but in reality only produce massively upsized files from its native 2MP imaging sensor. By contrast the two base models SJ5000 and SJ5000wifi have new 14MP Panasonic sensors and the SJ5000+ bumps up to 16MP. The number of pixels doesn't tell the whole story though and a I'll start with aquick resume of the type of requirements which govern Action Cam optical design. Small overall size and light weight is one of the factors. The GoPro aesthetic is of wide angle view with fish eye distortion. This type of lens has a deep field of focus so it is possible to have a fixed lens, (no autofocus) and have everything sharp from a couple of feet away to infinity. Fisheye lenses for large sensor cameras such as DSLRs are heavy and expensive. GoPro style cameras use a small and cheap vesion with correspondingly small sized imaging sensor, in the case of the SJ5000+ a 1/2.33" Panasonic MN34120PA CMOS type. It's dimensions are a tiny 5.8x4.3mm, close to those of the sensor of an iphone 5 and considerably smaller than that of a DSLR which has sensor dimensions 36x24mm.

With that in mind any assessment of image quality needs to be realistic and take the physical limitations of the camera into consideration. Small sensors invariably exhibit more noise especially in High ISO low light situations and dynamic range is limited.

I have seen some impressive images shot with mobile phones and the potential for decent stills quality (if only under ideal conditions), piqued my interest in buying and trying an SJ|5000+.

First off, the fisheye look is not one for all subjects the ultra wide angle makes even middle distance subjects appear to be a long way away and don't even think of photographing your nearest and dearest close up unless they can tolerate being portrayed with a huge nose.

The following images of Exeter Customs House on the Quay show what can be achieved with a little massaging in Photoshop. Remember all these images are my copyright and may not be copied and published elsewhere. If you wish to refer to them please link to this blog.


First the original image sized down to 1200 pixels wide:

The first impression is that it is drastically oversharpened making it look very gritty and accentuating noise.

This is demonstrated with the two examples below both 100% crops. The "Befores" are as shot, the "Afters have had a slight blur and some smart sharpening and noise reduction in Photoshop,

Before

 

After

 

 



 Before

After

 

Despite this there are still visible sharpening haloes and artefacts. A shame as it would have been possible to include a choice of sharpening strengths in the image menu so that it could be applied at the proper stage in post processing.

 

 



I was pleasantly surprised by the performance of the lens which is essentially a $2.99 item sold on Alibaba. Detail is held to the edge of the frame and the aggressive sharpening that the camera applies really isn't necessary. What isn't a surprise is the high level of chromatic aberration exhibited. This is of the blue-yellow variety and can be seen in the 100% crop sample from the right hand edge.

 



Before

 

The "After" crop below has had B-Y chromatic aberration correction carried out in Photoshop at a level of +66.6 which reduces it somewhat, however there is purple fringing visible at high contrast boundaries which is more stubborn to fix.

 

After

The final image is a 1200 pixel version of the final image  which has additionally been brightened using curves, straightened cropped and had  bit of de-fishing applied.

The conclusion is that with some light post-processing quite usable still images can be produced provided care is taken not to overexpose. Unfortunately for use in professional publication the aggressive sharpening applied in camera limits the size at which they can be reproduced, however quality is adequate for display at full size on a 4K ultra high definition TV screen.

There has been some debate over the accuracy of the SJCAM SJ5000+ AWB (automatic white balance). This interior shot was taken in a glass roofed conservatory lit indirectly room on the north side. Sunny day blue sky and clouds outside. I can only say that colours look absolutely spot on to me. Exposure set to -0.3EV and image brightened slightly in post processing.

SJCAM SJ5000+ a bargain GoPro?

Occasionally a brand becomes so pre-eminent that it comes to signify a whole genre. In the case of Hoover it mutated into a verb and even Dyson households still hoover their carpets. Thus has the GoPro brand become pre-eminent in the field of tiny video cameras in clear plastic waterproof boxes which can be attached to vehicle or person. Otherwise known as Action Cams these little protuberances have sprouted from every type of moving object, motorcycle, skier, quadcopter or can be seen waving about at the end of every 20-something tourist's selfie pole. The GoPro itself is now a mature product having evolved through several generations but its premium price left a hole on the market for copycat versions. The inside of a GoPro is essentially a beefed up version of the simple board camera used in countless surveillance cameras mated to a fixed focus fisheye lens. All of these components are available off the shelf needing only tooling up for a plastic case to produce a "knockoff" known in the vernacular of Action Cams as a "NoPro". Formerly these anonymous copies from Chinese factories were of inferior performance but one manufacturer, SJCAM has been attempting to raise its profile as a brand with its new SJ5000 models with specifications pitched towards the middle of the GoPro range but selling for a third of the price. The flagship model is the  SJ5000+, (SK5000 plus), priced at $169, and when the specification was announced the inclusion of an Ambarella A7LS75 processor related to that in the GoPro Hero3 Black and a true 16 Megapixel Panasonic imaging chip set up a ripple of anticipation late in 2014.

There is considerable irony in SJCAM's situation as GoPro competitor as whilst the wealth of the GoPro brand has protected it from any significant counterfeiting by sale of "clone" cameras, SJCAM has been plagued by various backstreet manufacturers of fakes which are indistinguishable from the genuine article. These may even perform similarly but have no guarantee that there will be technical backup or updated firmware. This has led to SJCAM taking steps to protect their brand by putting a scratch and check sticker on product boxes and having a system of certification for approved resellers. However it is a jungle out their and buyers are advised to avoid incredible offers and buy from sources with robust refund policies. My own SJ5000+ was bought from HERE through AliExpress and communications with them have been swift and efficient.

Whilst SJCAM are trying to build their reputation as a trusted brand name the launch of the SJ5000+ has been in danger of undoing their good work. Early models shipped in late 2014 were plagued with problems with buggy firmware and a hardware issue with the shielding of the wireless antenna. Thanks to a dialogue between the manufacturer and members of the Radio Control community these have been addressed to some extent.

At the moment though the SJ5000+ is something of a work in progress. For example I am still attempting to get the wifi feature on mine to work reliably and other users report some quality control issues which have required units to be returned which is inconvenient for those trading directly with sellers in China. My initial trials though have shown that video and stills can be very good and I believe that the camera has real potential to compete with GoPro in terms of the quality of videos produced. The potential for high quality 16Megapixel stills puts it a big jump above the earlier SJ4000 which had only a 2Megapixel sensor.

If SJCAM have aspirations to rise above the other "me too" manufacturers of NoPros then how they deal with the development of the SJ5000+ is crucial. It is important that they continue to listen to their buyers and address any hardware problems which come to light by offering exchange units and by developing firmware especially to release extra features as a reward to early adopters.

My SJ5000+ arrived from China yesterday and I'm just checking it out. First impressions of video and stills are satisfactory.