Saturday, November 01, 2014

Dell Inspiron 13 7347 Review

UPDATE 21 November:

Sadly, I can no longer recommend this particular model.  It has a severe design flaw in the touch screen that causes "ghost touches" - and based on my research and the reports of others on the Dell support forums, this is not an isolated issue.  Unit replacement most often does not address the issue, hence my unit is not a lemon unit.  Since Dell makes refunds very difficult and my feeling is repair or replacement won't help, I am keeping the notebook (but disable the touch screen when it acts up).

http://en.community.dell.com/support-forums/laptop/f/3518/t/19607216



I recently found myself in need of a notebook.  I haven't bought any such thing in over five years (the employer-supplied notebooks - a variety of Dell Latitudes and Toshiba Porteges - have proved more than useful).  However my office notebook isn't due for refresh yet, and I was getting tired of hauling its magnesium-skinned bulk around.

As my wife had recently gotten a Toshiba Portege Z30, which weighs an amazing 2.65 pounds - I decided that weight would be my major selection criterion.  But I also wanted a full HD (or higher) IPS screen, and a backlit keyboard.  And the notebook would also need to be cheap.

The above set of criteria are very, very hard to meet (even the Portege Z30 and ThinkPad X240 do not meet all of them, and these laptops cost a lot more money than I was willing to pay).

In the $1000 range, the notebooks which meet most or all of the above criteria are the Lenovo Flex 2 13 (which weighs about 4 lb), the Asus ZenBook UX303LN and recently-discontinued ZenBook UX32LN (the UX32LA and UX303LA don't have IPS screens), the Dell Inspiron 13 7000, and of course the Macbook Pro Retina 13.

I am no Apple fanboy (I have a lot of Android devices) but let's get this clear - the Macbook Pro Retina 13 is overall the best choice. It has the highest-resolution display (although not the highest-contrast); the fastest SSD (that isn't field-upgradable); the fastest processor (a special model i5 that only Apple gets); the best build quality; and by far the longest battery life. However, the 128GB SSD model (the lowest-end one) was at the high end of what I was willing to pay, and the 128GB SSD is small.

On paper, the ASUS UX303LN comes very, very close to the MacBook Pro Retina 13 in terms of specifications, and the ASUS has an Nvidia discrete graphics solution.  However it costs more than the 128GB SSD MacBook Pro Retina 13 (and a bit less than the 256GB SSD model) and doesn't come with an SSD.

The recently-discontinued UX32LN costs less than the base MacBook Pro Retina 13, also has discrete graphics, but no SSD.  Both ASUS devices weigh about 3.2 lb, slightly less than the Apple, but when you heft them in your hand, the difference in build quality is obvious (even though the ASUS notebooks also have aluminium chassis). The ASUS notebooks have decent battery life as well, but they can't match the Apple.

The Lenovo Flex 2 14 is probably the cheapest option you can get at this time (October - November 2014) with a full HD IPS screen.  It is a pentile screen and not as good as the other FHD screens. The large downside with the Lenovo is its 4 lb weight.  Battery life is acceptable.

My fourth option was the Dell Inspiron 13 7000.  It is available in two models, a 1366x768 IPS, and a full HD IPS. The latter model costs more (about the same as the ASUS UX32LN) and has the downside of not having a discrete graphics solution (it uses the Intel 4400).

I made a handy comparison guide of these notebook candidates:


The last parameter is how long (in hours:minutes) each notebook could loop the "Big Buck Bunny" movie before running out of charge.  It is obvious from this comparison that the MacBook Pro Retina 13 is the best overall choice, but also the most expensive, and this is the base model only with a 128GB SSD. Prices are in SGD, but the other ratings are from notebookcheck.net.

Note that the usual suspect high-end notebooks (Lenovo ThinkPad X1 Carbon, Lenovo ThinkPad X240, Lenovo Yoga 2, Toshiba Portege Z30) are not on this list, for the simple reason that they cost far more than I am willing to pay.  It was quite a shock to learn that high-end notebooks actually cost more than their Apple competition.

What the above spreadsheet does not show is the level of build quality of these notebooks, something you can't see unless you physically handle them.  As I have already mentioned, the MacBook Pro has the best build quality, the best trackpad, and the best keyboard.  It's the most solidly put-together.  The Lenovo Flex 2 14 is also pretty solid, but its weight goes against it.

From the spreadsheet, it looks like if you can't or don't want to spend money on the Apple, the ASUS is the next best choice, and on paper it is.  However, it doesn't feel as well put-together.  The reason I ended up with the Dell is because the Dell simply feels more solid in the hand, for the same price, in spite of the weak integrated Intel Graphics.

I used to have an ASUS with Radeon graphics, and - it's not all it's cracked up to be.  Certainly you can play most modern games, but the battery life with the discrete graphics enabled is a dismal one hour or so.

Now that I've put a reasonable amount of time into the Dell, these are the conclusions I can make:
  • The screen is very good; certainly the Retina is better, but having used 1366x768 matte TN panels for almost a decade, this screen is an eye-opener.
  • The build quality is above average; as the notebookcheck review points out, the build quality is more Latitude-level than Inspiron-level and is the main reason I chose this model over the ASUS UX32LN which has a better spec and significantly longer battery life.
  • The Yoga-like 360 degree rotation (that turns it into a huge ungainly tablet) is actually a useful gimmick.
  • However, Windows 8.1 on this device doesn't quite cut it as a tablet OS. In spite of the vastly more powerful processor, my Nexus 7 2 works better and is more responsive as a tablet than the Inspiron. However the Nexus 7 2 can't run Microsoft Word, so there is that.
  • The touch screen is less responsive than that on the Nexus 7 2 (which also is a Full HD IPS touch screen). It is sometimes necessary to press harder or multiple times (particularly with the included passive stylus) to get click registration.
  • The track pad on the Inspiron 13 7000 is of mediocre quality, particularly the click-over feel is rough and the actual feel as you move your finger over the trackpad is also rough. The track pad on my employer-issued Dell Latitude E6320 is far, far better, and the glass pad on the MacBook Pro is beyond comparison that it's not even funny.
  • The keyboard is also only acceptable, my employer-issued Latitude E6320 is also better. However the Inspiron keyboard is illuminated (only two illumination levels however). The notebookcheck review noted the excessively-small backspace key.  Another niggle is the absence of Page Up and Page Down keys; you need to press Fn-Up Arrow and Fn-Down Arrow. I can still type at a reasonable speed on this keyboard, so it's acceptable. It is important to point out that the Dell Latitudes are a higher grade of notebook and generally cost much more.
  • Of all my candidate notebooks, the Dell has the worst battery life (four hours on Big Buck Bunny).
  • However the Dell Inspiron 13 7000 is reasonably light, practically the same as the MacBook Pro Retina 13.
In conclusion, the selection of (approximately) 3 lb notebooks is rather thin, particularly if your budget is limited to around $1000.  You can't get perfection in this price class, unless you're willing to pay a bit more and live with a small SSD in the MacBook Pro Retina.

Another conclusion I've come to - if you are spending $1500 and up on a flagship notebook, forget the so-called premium notebooks from Lenovo, ASUS, HP, etc.  Just get an Apple device, they actually provide better bang for the buck and unsurpassed battery life and build quality. That's assuming your applications run on MacOS X.

So the Dell Inspiron 13 7000 is a good compromise, but a ways off from perfect.  It was the least compromised choice for myself, but someone who wanted longer battery life and a discrete graphics solution would probably find the ASUS UX303LN or UX32LN to be a better choice overall.

UltraBookReview has a good review comparing the ASUS UX303LN to the MacBook Pro Retina 13. The mere fact that the ASUS is favorably compared to the Apple device is already quite a big vote in favor of the ASUS. The UX303LN simply was a bit too much money (about $300 more than the Inspiron 13 7000) for me, and the UX303LA while about $300 less than the Dell, didn't come with an FHD IPS screen.

Saturday, October 11, 2014

Skywatcher Star Adventurer Tripod

I wanted to find a more suitable tripod than the flimsy Benro A350EX, and less clumsy than the Vixen Polaris tripod.  I initially purchased a Sirui N2204X, carbon fibre, with detachable leg, etc. It was not terribly stable (about 4-5 seconds damping time) in spite of its alleged 33lb rating.


But, due to a 20% discount promotion at KEH, I was able to purchase a beat-up Gitzo G1340 Pro Studex tripod, without centre column.  That last part is important, because the centre column induces instability. Coupled with the rubber bungs on the Gitzo's feet, damping time is now 2-3 seconds. The Gitzo is actually more stable than the larger aluminium tripod from my Vixen Polaris. This is a tripod that's rated 20lb.  The total weight of this setup (Stellarvue SV80ED, diagonal, eyepiece, mount, and tripod) is just a hair under 20lb, and can easily be lifted and carried around.

Of course, Gitzo tripods are eye-wateringly expensive new; a major drawback.  A new 2-series Gitzo carbon tripod and the Star Adventurer would cost very close to an Atlas or EQ6, so definitely not cost-effective anymore.


I guess we all can derate Chinese tripod weight ratings by 50% now..

Sunday, September 21, 2014

Sirui R2004 Tripod for Astronomy

I was looking for a lightweight tripod that would fit in carry-on baggage and be useful for my Star Adventurer.  The Sirui R2004 tripod seemed like the perfect fit: it is 520mm collapsed (will fit diagonally into a carry-on suitcase), weighs about 1.8kg, and is rated for 15kg.

It also only costs S$85 ($68 US) which is mind-bogglingly cheap.

All of the Sirui 2-series tripods (R2xxx, N2xxx, T2xxx) have 28mm thick legs, only differing in the number of leg segments, whether one leg can be detached to form a monopod, and the material of the legs - aluminium or carbon fibre.  The R2004 is the most basic model, and hence the cheapest.

As payload I used a Sky Watcher Star Adventurer, APM Lomo 80mm apochromatic triplet in a William Optics tube, 2" Televue diagonal, and a 4mm Vixen LV eyepiece giving 120X magnification.  The total weight of all this is 8 kg, well below the alleged 15 kg capacity of the Sirui tripod.

The long and the short of it: at 120X, it takes a mind-boggling 8 seconds for vibrations to damp out after touching the focuser. Hence this tripod is wholly incapable of carrying the mentioned load.

As a control, I used the short aluminium tripod from a Vixen Polaris; this has the benefit of much larger legs, is much shorter, and has a tray to reinforce the legs.  With this tripod and the same mount and telescope, damping time is reduced to 4 seconds, which in my opinion is still excessive.

In short, the Star Adventurer is overloaded with the Lomo 80mm, and the Sirui tripod is also overloaded with an 8 kg load. Of course 120X is equivalent to 6000mm focal length.  So the Sirui tripod and Star Adventurer may still prove useful for astrophotography.  But as a visual setup for planetary, this combination is unusable.

Friday, July 25, 2014

Sky Watcher Star Adventurer, Part II

I had an old counterweight shaft and counterweight for an EQ1 mount lying around (the EQ1 had already broken some years back and I had thrown it away).  The shaft has a large-pitch thread on one side, and an M6 tapped hole for the toe saver on the other side.

I drilled out the M6 tapped hole with an 8mm bit, then epoxied an M8 bolt into the hole.  I then cut off the head of the bolt leaving the M8 threaded portion exposed.  A more robust solution would have been to drill out the M6 hole with a 6.5mm or 7mm bit, then use an M8 tap to cut threads into the hole.  The M8 bolt would then screw into the threaded hole, a more secure fastening than just epoxy.  But I did not have an M8 tap handy.   The epoxied bolt seems secure enough (I used Araldite brand epoxy) and hasn't wobbled through a 2-hour plus testing session.



With the stock EQ1 counterweight, the Stellarvue SV80ED still would not balance; however the result is much more in balance than having no counterweight at all.




However, the counterweight did not really improve the guided performance, or reduce the periodic error to in any meaningful way (and I did not expect it to).  Guided performance is still around 2" RMS, which I believe is the best this mount is capable of.  Hence it should be used at a pixel scale of 4" to 6" per pixel, or 200mm to 300mm focal length.


A longer sampling period has confirmed that the worm fundamental is 10 minutes, hence the worm wheel has 144 teeth (like the Vixen Polaris, Great Polaris, and CG-5).  This was confirmed by a poster on Stargazers Lounge who tore down the Star Adventurer.  The fundamental is about 30" peak-to-peak.



I got a better polar alignment this time (as shown in the minimal DEC drift in the graph above) and in the process noticed that the polar scope is pretty well-aligned - better than my PASILL3.  It's not perfect, but it's good enough that I'm not going to mess with it.

Thursday, July 24, 2014

Sky Watcher Star Adventurer Portable EQ Mount

I purchased this portable mount in London from The Widescreen Centre in London (very close to Baker Street!) instead of lugging my old Vixen Polaris to the UK.  I got the "Astro-Photo Bundle" for £299.00 (about US$ 500) and am still waiting for the £40-odd VAT rebate, which would bring the price down to about US$ 400.  This mount is also available from Perseid in Malaysia for 1700 MYR, or about US$ 540.

The build quality is better than expected, with some nice touches such as the worm-and-sector drive for the altitude axis of the equatorial wedge, a design very reminiscent of the Astro-Physics Mach1 GTO, albeit with much slacker tolerances. There even is a ratchet on the altitude locking bolt (again, just like the AP). Here I have secured it via the 3/8" bolt to the aluminum tripod of the Vixen Polaris.  The mode dial and power switch is also visible here:



Right Ascension and Declination clutches are the large knurled plastic wheels.  On a less sturdy tripod, it is quite easy to knock off the polar alignment when tightening or loosening these clutches.


The declination slow-motion knob is visible in the photo below.  Note that the equatorial wedge, declination slow-motion, counterweight shaft, and counterweight, are all part of the "Astro-Photo bundle" and are separately priced if one purchases the base package.  On the other side of the Star Adventurer body are two electric RA slow motion switches (12X sidereal) to assist in centering objects, since tightening the RA clutch is a fiddly affair that tends to throw objects out of the field.


There is a fairly nice polar scope, although the reticle illuminator is attached to the far end of the polar scope bore, which is obstructed by the declination assembly.  Hence use of the illuminator requires removing the entire declination assembly (and any payload on top), which throws off the polar alignment.  The 4x AA batteries are under the top cover, and are supposed to last for up to 72 hours of tracking. Maybe that's with lithium batteries.


Below is a 100% crop of the area around Deneb, 2-minute exposures with a Canon 70-200mm f/2.8 lens at 200mm.  There is a bit of RA drift, and a much smaller DEC drift.  The RA drift is a combination of periodic error  and polar misalignment in altitude (as I only used the polar scope for alignment, this was in Lancashire in the UK).


On returning to Singapore, I decided to load up the Stellarvue SV80ED, and a Meade DSI.  Widescreen hasn't received their shipment of counterweight shafts and counterweights yet, so the mount was severely unbalanced (no counterweights).


Using PHD2 I was able to measure a bit less than 2" RMS error in RA, after guiding.  The Star Adventurer has a standard ST4 guide port, but only can guide in RA, since the DEC is not motorized.



Unguided performance shows about 23" peak-to-peak periodic error, and there is no PEC.  The worm period is about 15 minutes, although there is an almost-equal amplitude harmonic at 7.6 minutes.  This implies that peak periodic error over a 2-minute period would be approximately 6" - so unguided exposures at 200mm and of 2-minute duration should be possible. Guided performance should be acceptable at around 2" to 3" pixel scale, limited only by declination drift.  So a scope like the SV80ED would be a good choice if guided.  However, the mount is close to its limits with such a payload. A 200mm range camera lens or small refractor like a Takahashi FS60 is probably a better choice.



In summary, this mount is a far cry from my Mach1.  Although it looks better-built than other Chinese mounts, and some of the parts are CNC machined and not cast, the illusion of quality falls apart under close scrutiny.  That said, if you want something supremely portable for up to perhaps 300mm focal length, this mount will do very well.  It says something that the entire mount weighs not much more than a Mach1 Eagle half-pier (and also doesn't cost a lot more than said half-pier).

If I ever travel to Gran Canaria,  I will certainly not be able to bring the Mach1 along, but this mount will fit perfectly in check-in luggage.

I did manage to get about 30 minutes of the area around Deneb with the Star Adventurer from Lancashire, but I missed the Pelican Nebula by a small amount.  The wispy nebulosity next to Deneb that I thought was a DSO, turned out to be dirt on the DSLR sensor. D'oh!  image scale with the 200mm lens was about 6" per pixel.