Tuesday, 13 November 2018

Restharrow Scrape

Restharrow Scrape is a good place for birding you never know what your going to find on the scrape itself, but also the surrounding area has some great habitat for a wide variety of species.

Early misty morning looking out across Restharrow Dunes
7dmk2 @1/2000th iso100 F5.6 100mm

Whilst talking to a couple of visiting birders I saw one glance up, I followed his gaze and got this lovely shot of a hunting Kestrel
5dmk4 @ 1/2000th iso1600 F6.3 400mm
 I also dialled in +1.33ev to account for the bright background.

A short walk up the Ancient Highway towards the Chequers Inn I got these shots of Stonechats

5dmk4 @ 1/3200th iso400 F5.6 400mm

5dmk4 @ 1/1250th iso400 F7.1 400mm

Turned out to be a bit of a Stonechat fest, I did see Goldfinches, Robins, Linnets Great Tits, Blue Tits but they were to distant for good pictures all in all an enjoyable few hours.
 

Tuesday, 23 October 2018

The Murder Of Mary Bax

So I am out early walking between the Restharrow Scrape and the Chequers Inn I left the road as a bird was perched in a bush and I thought I would get a little closer only to stumble upon this headstone completely by chance and thought I would document what I have discovered about this sad event.

The inscription reads:
On this spot August 25th 1782
Mary Bax Spinster Aged 23 years
Was Murdered by Martin Lash, Foreigner
Who was Executed for the same.

I did a quick bit of investigation and the story goes like this (all though there are a couple of versions I believe this to be the true version),
The Ancient Highway was once the main route from Deal to Sandwich,  there were a number of buildings along the road, The Chequers Inn being one of them.

Mary Bax was a young woman of 23, on the morning of 25th August 1782 Mary was walking along what we know as the ancient highway from Deal to Sandwich carrying a bundle. She had just passed the Chequers Inn when she passed a man sitting by the side of the road. 
He stopped Mary and asked the way to Sheerness, which is a long way from Sandwich, then he asked her for money. 
Mary refused, the man who was a foreigner then attacked Mary, ultimately killing her and dumped her body in a ditch. 
He then made off in the direction of Sandwich carrying the bundle Mary had been carrying. 
The man did not know that he had been seen by the 13 year old son of a Looker, ( a Looker was a Sheperd) the boy was scared that he would share the same fate as Mary so he hid until the man was out of sight, then he set off in the direction of Deal and raised the alarm. 
It was found that the man Martin Lash (Laas) was a deserter from a ship anchored in the Downs, he was Norwegian and aged 27. 
He was finally found asleep with Marys bundle next to him, in a churchyard in Folkestone which is nearly 20 miles away from Sandwich. 
He was taken to Maidstone Gaol, tried and executed for the crime.
The stone still stands in remembrance of Mary Bax. 
I am glad that I chanced upon the stone.
I don’t think Mary was buried at this spot, as I found this entry:
"Mary Bax was buried at St Peter's Church Sandwich, her gravestone was cleared away in the last century to tidy the graveyard but is still recorded in the parish records."

Sunday, 21 October 2018

Lens Dilemma

Well I have'nt written on my blog for a few months and decided it was time to get it up to date, it's been an eventful time none the less.
Try as I might I just was'nt happy with my Sigma 150-600mm Sport, some results were excellent while others were shall we say lack lustre to say the least !

So I decided to take the plunge and sell it, it is no more !

Whilst on the subject of selling obviously we all want to get as much money as possible for our kit, selling on Ebay is going to cost you 14% of your sale price, to avoid this I posted my lens on Gumtree, I had three replies all of which were scam merchants, they say yeah want it and ask you to send payment details for your PayPal account and then they send you a dodgy email that looks like it has come from PayPal, saying that a payment has been received and will be held until a tracking number has been entered at which time the funds will be released into your account, yeah right ! 
The scammer then follows this email up with a " I have paid you can you dispatch today" they even say they will pay extra if you can get the item on next day delivery.

Don't fall for these scammers be careful with your stuff !!!

Next I have to decide what to replace it with, of course I would like to go out and buy a Canon 500mm f4 l is mk2 but even 2nd hand these beauties are over £6k so that is not going to happen, I just cannot warrant spending that sort of money on a lens, if I was earning a living from my photos it would be a different story.


Canon 7dmk2 Canon 100-400mm mk2 @ 400mm 1/640th f7.1 iso125

So the hunt is on, Sigma have a 500mm f4 in their armoury it has very good reviews, is the same weight as the Canon 500mm mk2 and according to a lot of the reviews I have read has a very similar image quality to the Canon version.
Currently the price for a new Sigma 500mm f4 is £4999 or very close to it everywhere I have looked I have seen it for £3999 on Amazon sold by a third party seller, I have emailed the seller but never had a response ! so that looks like a non starter.
Canon 7dmk2 Canon 100-400mm mk2 @ 400mm 1/640th f7.1 iso160
Other options are another Canon 500mm mk1 these can be had for around £2800 to £3800, mint condition being at the £3800 end of the scale.
I am tempted as the Canon 500mm f4 l is mk1 is a great lens, its also possible to pick up a Canon 600mm f4 l is for similar money, but is that going to be too heavy for my old bones ! and there is the repair issue should something go wrong with the lens, mk1's are getting a bit long in the tooth and are no longer supported by Canon.

Canon 7dmk2 Canon 100-400mm mk2 @ 400mm 1/640th f5.6 iso250

As soon as I have made my choice I will put a new post up about it.


Friday, 20 July 2018

Sigma 150-600 Sport Further Update On Auto Focus Micro Adjustment

After the loss of the settings from the AFMA table, I was miffed to say the least and decided to do a bit more work and report on the method and accuracy of the results.

As mentioned previously the Sigma 150-600mm Sport has the ability to be MA'd at 16 different points across the focal range using the Sigma Dock.
Unfortunately there is a lot of guess work involved, by this I mean you have to
  1. take a shot of your target, 
  2. review it, 
  3. remove the camera body from the lens,
  4. put the dock on make an adjustment, 
  5. remove the dock, 
  6. put the body back on
  7. repeat the process
This has to be repeated for all 16 points multiple times for each point, which is daunting and time consuming.

So I thought I would try and come up with a similar method or at least a more streamlined method.
The first thing I did was get a DOF calculator out, using the widest aperture and the following distances 2.6m,6m,15m and infinity @ 600mm gives the DOF as .55cm,3.34cm,22.9cm and 93.4cm
which is ok but you need a target with a front to back length of at least a metre if not more.

Repeat these DOF calcs @ 400mm and you get 1.36cm, 8cm, 52.2cm and 211.7cm
Repeat these DOF calcs @ 250mm and you get 3.72cm, 21cm, 135.1cm and 548.5cm
Repeat these DOF calcs @ 1500mm and you get 10.5cm, 59.6cm, 383.2cm and 1619.7cm
The infinity calcs were done at 30m which is questionable, and to be honest I never bothered attempt any infinity adjustments.

How the hell do can you see how accurate your focal point is when you have such a huge DOF ?
the smaller distances are fine you can easily see the edges of the DOF as the sharp edges become less defined.
As for attempting to MA 150mm @ infinity/30m I'm jiggered if I have a scale that is 16.197m long in me back pocket !

At this stage I kind of lost the will to live.

I  did MA the lens at all focal lengths up to 15m took a long time, I used Reikan Focal Pro, first off I used Canon's built in MA adjustment to see if the Sigma needed tweaking.
At 2.6m no adjustment required  across the focal range Reikan reported 0 was the correct setting
At 6m no adjustment required @ 150mm and 250mm, @ 400mm and 600mm it needed tweaking final setting of -5 and -3 respectively.
At 15m 150mm needed +1, 250mm 0, 400mm 0, 600mm +5

In my humble opinion whilst it sounds like a light bulb moment having all these focal points to MA at in reality and practically it is too much of a faff to use the Sigma Dock, whilst initially I had loads of enthusiasm for this facility it has gone down hill fast.

I will probably end up using the inbuilt Canon MA and just MA it at 150mm and 600mm and be done with it !
Life is too short to be spending any more time on it.

Sunday, 15 July 2018

Strange But True

Recently the results I have been getting with my Sigma 150-600 have been somewhat dismal, so today I connected it too the Sigma USB Dock and checked the AF settings only to discover that the entire AF table was empty !!

Note to self: next time write the bloody settings down !!!!

What has happened to em I dont know but that will hopefully explain the soft focus results I have been seeing of late.

Now all I have to do is go through the long drawn out process of setting it back up grrr !

Monday, 7 May 2018

Sigma 105mm f2.8 EX DG OS HSM Macro Lens

Originally I had the Canon 100mm F2.8 mk2 and whilst it is a cracking lens I didn't use it that often, and as my photography had taken a turn towards wildlife I decided to sell the Canon 100mm lens and put it towards a Canon 500mm f4 L IS (which has now also been sold as Canon decided it had come to the end of its life).
So when I read a review in Photoplus of a bunch of macro lenses  the Sigma 105mm f2.8 EX DG OS HSM Macro Lens came out as best value for money winner, at £360 whats not to like, its half the price of the Canon equivalent and almost matches the Canon on the image quality stakes.

After hunting around on the good old WWW and doing the necessary research I took the plunge, found one on sale at Mathers of Lancashire for £339 including delivery.

I ordered on the Thursday not expecting to see it until the following week, but i was wrong there, phone call from Mathers asking if i needed a filter for the front and informed me it would be on its way the same day for delivery on the Friday before 1pm !
True to their word it rocked up about 10.30am, fantastic service from Mathers!!

So far all I have done is MA'd it too my 5dmk4 using Reikan Focal, it needed a setting of  +2 to get the focal point on the money.
Other than that it looks like a good bit of kit for the money.

I will update this post when I get it out in the field.

Wasn't entirely happy with the MA results from Reikan Focal so I decided to do it old school on my home made ma test scale.
Aperture set to f2.8 iso 200 manually defocusing to both sides of the focal point  this is what I found.

 The above is the result using Reikan focal a setting of +2 on the MA scale, looking at this picture to me there is a slight back focus on this setting.

The above I have set MA to +20 which gives a big front focus.

On this one I have set MA to -20 which gives a big rear focus

Finally I have set MA to 0 and looking at this result I am happy that this is where it should be set.

All of these results are after multiple shots defocusing between each shot manually to ensure a consistent result.

A quick whizz into the green house for a tester shot.

Shot using a tripod f14 iso200 1/320th 105mm
So far pleased with this lens !




Gimbal Head Update

OK so I bought one of these NEST   NT-530H Mk2 some time ago,
Nest NT-530H MKII Carbon Fibre Gimbal Head
 Got it from these guys UK Digital


and I do love it, don't get me wrong, there is  no slop in the bearings etc good solid construction, great features:

  • - 10 layer Carbon Fibre
  • - Precision bearings
  • - Arca-Swiss compatible
  • - 360 degree pan
  • - Load capacity of 25kg

My one gripe with it is that it is far from free moving.

After putting up with it since I have had it hoping it may free off with use I decided to strip it down and have a look at what makes it tick!

3 Alan bolts on the top removed the carbon fibre head leaving the horizontal rotating bit behind this is held in place with another larger Alan bolt which in turn has a plastic washer and a bearing race, once that is off  there is a black outer casing followed by the inner workings.
I have never in all my days come across anything so sticky as what was on the main bearing, whilst it might do a good job of lubricating the bearing it is this goo that gives you the damping effect and makes the head somewhat hard to rotate, and for BIF shots etc it makes life easy if the gimbal head moves freely.
I was impressed with the construction, precision and quality of the bearings is very good it is just the goo that spoils it for me.

So I dunked it all in some white spirits to remove the sticky goo and repacked it with High Melting Point Lithium Grease, whacked it all back together and hey presto beautiful smooth rotational movement, just what the doctor ordered

As for the up / down axis I have left that with the sticky goo as that stops your lens / camera setup doing a rapid nose dive if you haven't got it balanced correctly.

A quality bit of kit at a reasonable price only spoilt by the goo they put it together with.

Tuesday, 24 April 2018

Restharrow Scrape 20.4.18

A cracking morning light winds, bright sunshine great conditions, arrived about 0800 for today's outing I am using Canon 5dmk4 and Sigma 150-600 Sport.

Surprisingly I was all alone in the hide this morning, not a great lover of Greylag Geese but I did feel a bit sorry for this one individual, there is a pair of Swans nesting over the far side of the scrape and Mr Swan, here just flexing his muscle,

1/1250th @f9 iso400 600mm

was being very territorial, he would not leave this particular Graylag alone.

1/1250th @f8 iso400 600mm

Then a pair of Canada Geese dropped in and one of them decided that (I assume it was the he) he was going to get the same Graylag and continued to chase it for some time,

 1/1000th @f11 iso1000 600mm

 1/1250th @f11 iso1000 600mm

which gave Mr Swan a breather.

Next up Mr Swan decided he had had enough of this shenanigans and set about the Canada Goose, it really was quite entertaining !

 1/1000th @f8 iso400 600mm

1/1250th @f8 iso320 600mm 

Eventually they all calmed down and started to go about there own business !

There was also Northern Shoveller, Gadwall, Shell duck, Little Grebe, Coot, Mallard, Lapwing and Tufted duck on the scrape.

Saturday, 21 April 2018

Oare Marshes 16.4.18

First day out for ages, beautiful sunny morning arrived at Oare  about 0700 bit late really but hey ho.

Overall pretty quiet walked along the sea wall and up the estuary, first decent spot was a Peacock Butterfly on Hawthorn blossom, kit for today is the Canon 7dmk2 with my Sigma 150-600 Sport.

1/500th @ f8 iso200 600mm
It just sat there displaying those big scary eyes, I couldn't resist a shot of it.

Shortly after that a few bearded Tits put in an appearance but they just wouldn't sit nicely, just couldn't get a good clean shot, the best I could do was this one.

1/400th @f8 iso200 600mm

Plenty of Sedge Warbler activity again getting a clean shot was the issue, it was just one of those days where the birds just didn't quite perch in the right spot, this Sedge Warbler I watched for 20 minutes it was displaying and singing using the same bush, it would fly up into the air hover and dive down into the base of the bush, then work its way back towards the top.

1/400th @f8 iso200 600mm

Again it never sat in the right spot clear of twigs and shadows !

1/250th @f8 iso200 600mm

None the less an enjoyable walk round Oare.

Thursday, 1 March 2018

Data Recovery

Ever had that sinking feeling when you get home from a good shoot and you go to transfer your shots from your memory card to your PC etc and find that there are no pictures to transfer AGGHHHH !!!
Touch wood this has not happened to me, but my friend Dave had just been on a once in a lifetime Safari only to discover that the memory card that had most of his shots on had some how been corrupted !!
So what do you do in a case like this ?
First thing is don't panic there is normally a way to recover your lost treasures.
Ideally if you are on the ball with PC's create an image of the card before you do anything else, that way you always have a safety net, mount the image you have just made and do all your data recovery attempts from the image, this way you don't touch the original card.
OK next stop is the card makers website and look for support, most of the manufacturers have free recovery software available that will (unless the card is totally fried) recover your files.

So you download and install the software point it at the image, failing that use the card, the software will then ask you to select a few bits and bobs and then run a scan of the image / card, if you have set your PC/ Laptop to sleep after xx minutes disable it, you do not want to interrupt this scan !! even if it looks like the scan has stopped let it run to the end, if it crashes try again.
Once the scan has completed it should list all the files available for recovery select them and a destination and away you go.

Preferably before you tackle the dodgy card format one of your other memory cards and do a dry run to see what you can recover form a good card, just so you don't make a costly mistake with the dodgy card and lose your data completely, that's why working from an image is safest.

It is surprisingly difficult to lose data, even if you format a card all the images will still be there, when you format a card all you do is remove all the flags and pointers that tell the controller what areas of the memory contain data.

What do you do once you have recovered your precious pictures from your card ?
Well obviously you will lose confidence in the cards ability to record data accurately, I mean you wouldn't want to go on another important shoot and use that card right ?
Before you bin it format it in the normal way and then fill the card up with data if it is 32Gb write 32Gb worth of files to the card and then try to read them back to your PC, do this several times to test the cards integrity.

Its then up to you what you do with the card based on the results of the test, personally if it performed the test flawlessly a number of times, I would use it again but not on anything crucial to start with.

Finally if the above recovery procedure doesn't recover your files most manufacturers provide data recovery services for their cards, some charge some don't depends on the card type age etc but its a good last resort.
Even if the card is totally unreadable by the likes of you and me, they can pop a card open and bypass the memory controller and read the memory direct.

Fingers crossed it will never happen to you but if it does I hope the above may help you to recover your files.

The Beast From The East

Well its too bloody (windchill -7) cold for me too go out birding, so I just kept an eye on the back garden and there has been lots of activity, plenty of Blackbirds, Blue Tits, Sparrows, Starlings, Dunnock, Wren, Robins, Magpies and a solitary FieldFare which has been in the garden for the last two days now.




 Shot through the double glazing so quality is not as it should be.
Far from being a social bird this FieldFare has been guarding the bits of apple that I put out as if its life depended on it (and well it may), as soon as a Blackbird or Starling went anywhere near the apple he was on it fighting off all intruders, the only company he would tolerate was the Sparrows as I assume he knew they were not competing for the same food.
The only time it took flight was if I stepped outside to top up the feeders or if the Magpies dropped in.
The Wren was busy looking under the coping stones on my Barbi wall and frequently found a juicy morsel.
Blue Tits checking out the bird box and feeding on the sunflower hearts.
Starlings were giving the fat balls some welly, Blackbirds were attempting to pick up the bits from the fat balls that the Starlings were dropping but the FieldFare was relentless in scaring them off !

Wednesday, 14 February 2018

Sigma 150-600 Sport Auto Focus Fine Tuning Update


Well after hours of searching I haven't been able to find any Canon shooters that have worked out the ratio (if there is one) between Sigma and Canon AF adjustment scales.

I spoke to Sigma support nice chap by the name of Daniel he explained the following with regard to the AF fine tuning with regard to the above set of figures I found, the x20, x40 x60 x80 etc figures are used by Sigma for testing and setup, however he explained that the distances used via the usb dock are indeed the ones to use for fine tuning the AF system.
Using the distances in the software will give a better AF performance across the entire focal range than using the x20, x40 method.
He also said to start at the 2.6m end of the scale and work up toward infinity at the various focal lengths, again stating that this will give a better result across the entire focal range.

So that is good enough for me straight from the horses mouth so to speak, that is what I will endeavour to do !!



















Thursday, 1 February 2018

Auto Focus Micro Adjustment and the Sigma 150-600 Sport

Well this seems like a daunting task ! but probably one that will make the auto focus accuracy extremely good right across the focal length range so its worth persevering with I think.
The Sigma has the ability to be programmed at 16 yep 16 points across its focal range, unlike a Canon zoom lens which can only be micro adjusted at its shortest and longest focal lengths, the Sigma can be adjusted 150, 250, 400 and 600mm.
Not satisfied with that Sigma have gone one step further and allow you to adjust the auto focus accuracy at 4 distances to subject at each of the four focal lengths.
However in order to make any custom adjustments you first need to purchase the Sigma USB Dock (£40) my first thoughts were, this really in my opinion should come with the lens and not be sold as an accessory ! upon reflection I would assume that not everyone will use it.
You also need to download the software Sigma Optimisation Pro from the  Sigma Website

Once installed you then have the ability to customise the lens parameters, update firmware as and when updates are available all in all its a pretty nifty bit of kit, as always improvements could be made.
The first improvement I would like to see is the ability to save a customised profile to disc for later use, this would then allow you to create profiles for each camera body you use the lens with, as it stands if you adjust AFMA for the main camera body that the lens will be used with when you come to switch it to another camera body all the AF settings you have programmed in will not be accurate as no two camera bodies are alike.
This issue must be an easy fix as the first thing that happens when you connect the USB Dock to the lens and PC is it checks for the firmware version of both dock and lens and then reads the current  configuration from the lens, which creates a temp .bin file on disc, that's as far as I have looked, someone with a bit more coding knowledge may well be able to knock up a routine that can save this .bin file and give it a meaningful name for later use, if that would work I don't know.

So how to go about adjusting AFMA, as far as I see it there are two options
  1. you either take the test shot analyse it, remove the lens connect it to the dock and pc make the adjustment via the software put the lens back on the camera and take another shot and repeat above for each adjustment for all 16 points !
  2. Use the camera bodies AF adjustment write down all the settings and apply them all in one go. 
Both of these methods have issues, the first you will be forever taking the lens off and back on of the camera this seems to me like a lot of messing about and a very long drawn out process !
The second does the Canon AF adjustment scale directly match the Sigma AF adjustment scale, both have the same range of plus or minus 20 ?

 Main Menu View

 Auto Focus Adjustment View
If it does happy days  I will email Sigma support to see if they know the answer to that one.

Well that's answered that one the man from Sigma he say "no"


"It does not relate to the Canon scale in any way.  If needed please input small values to see the difference and adjust accordingly."

Oh well at least that has cleared that one up !!

So today I thought I would have a little bash at seeing how good the focus is out the box, I have only tested @ 3m  distance to subject and f6.3 or wide open for this lens :
@ 600mm I found the focus to be pretty much smack on

 600mm
Using my home made focus chart it is clear that the red text is pin sharp and the 2 and 4 are pretty equal as you move away from the centre line, no adjustment required here.

@400mm it looks to me like there is a slight back focus  the red text is still sharp but as you look at the scale above and below the centre line 2,4, 6 above look a little sharper then 2,4,6 below
 400mm
@250mm again this is clearly back focusing the red text is still pretty sharp but looking at the scales the above scale is way sharper then the scale below
250mm
 Finally @150mm this one looks a bit soft all over (but that is probably my fault) but still seems to be exhibiting some back focus
150mm
So what I will do next just for the sake of it is repeat this test and adjust using the Canon adjustment and then again using the Sigma adjustment to see if there is any comparison.
I have read up on this in some forums and it appears that for Nikon cameras the ratio is 2 to 1, 2 steps on the Sigma scale equate to 1 step on the Nikon scale.
I havent found this information online for Canon yet.
But that's a job for tomorrow !!




 

1st Time Out In The Field With Sigma 150-600 Sport

The first decent day since the new lens arrived so I took myself off to Bossenden Woods, I have not made any AFMA adjustments to the Sigma as I wanted to see how it performed straight out of the box.
Compared to my Canon EF 500mm L IS the Sigma is a light weight, having said that it is very well built, I have changed the tripod mount from the one supplied with the sigma to funnily enough the one I had on my 500mm, Sunway Foto LF-C1 fits perfectly.
I changed it for two reasons:
  1. The one supplied does not give sufficient clearance between the foot and lens barrel to carry the lens comfortably, there simply isn't enough clearance to get my dainty little mits in there without gloves on, with gloves no chance.
  2.  The new foot is an Arca Swiss compatible so fits straight onto my Gimbal Head.

The Clearance between foot and barrel on the original mount is 15mm with the new foot it is 40mm which is more than enough and makes it easy to carry by the foot, (Sigma take note!!).
 First impressions go along way, the results I have from this Sigma lens on its first outing to me easily match my old Canon EF 500mm L IS output and as I said I have yet to set the AFMA so it can only improve a little !
The background bokeh doesn't look quite as nice as the Canon 500 but that is a small price to pay when saving £5000 or there abouts and there was a 2 stop difference in the pictures below so again the bokeh could improve when the same stop is used.

Canon 5D MK4 Canon EF500mm F4 L IS +1.4x (700mm)
f9 1/800th ISO1600

Canon 5D MK4 Sigma 150-600 Sport @600mm
f11 1/100th ISO800

One might ask is it fair to compare a prime lens to a zoom lens, well in this case I think so as the zoom lens was purchased to replace the prime lens.
Next job is to check the AF accuracy but that will be another post.

Tuesday, 23 January 2018

Canon EF 100-400 f4.5-5.6 L IS ii

With the money I got for my Canon EF500mm f4 L IS not only did I order the Sigma 150-600 Sport I also ordered the  Canon EF 100-400 f4.5-5.6 L IS ii as well and still have a little left over.

This arrived to day ordered last Thursday from the good people at Portus Digital always great prices and excellent service I have no problems recommending them.
OK so it is what is called a "Grey Import" but to be honest it comes with 3 years warranty from Portus Digital and the savings are massive, I paid £1319 for this lens including delivery, cheapest UK stock £1799, thats £480 saved.
Portus Digital have been around for a long time, the guys there are only too happy to help so whats not to like.

I tried this lens in the garden during a brief sunny spell on my 7dmk2 straight out of the box


I am more than happy with the resulting image, so it looks like good times ahead for that combination !

Monday, 22 January 2018

Grey Imports Should You Shouldnt You ?


What Are Grey Imports?

A grey import is equipment that has been supplied by a manufacturer in a different part of the world, for example supplied by Canon Hong Kong to a shop in Hong Kong, and ends up being sold on to you in the UK.
This equipment may be purchased by you directly from a shop in Hong Kong (meaning you are importing it yourself into the UK), or it could be imported into the UK by another company and then sold on to you.
The key point is that the manufacturer has sold it into a different (not UK or EU) geographic market, and someone else is then importing it into the UK.
Grey imports are normally a lot cheaper, but there are also some downsides that you should be aware of and take into consideration.

If You Get A Good Deal Should You Care?

If you buy a grey import, it doesnt neccessarily come with a valid UK manufacturer warranty.
This means the UK branch of the manufacturer would not offer free warranty repairs in the unlikely event of something going wrong within the warranty period (typically one year).
You would therefore have to rely on the shop to provide warranty repairs instead.

There may be other issues such as the manuals being in the wrong language, (from Portus Digital this has never been the case in my experience) or the item not having a UK plug. These are pretty minor.
Depending on how you purchase the grey import, you may be liable to pay import duty and UK VAT in addition to what you are paying the shop,( again from Portus Digital the price you see is the price you pay) and this can make the price considerably less attractive.
Personally I would never buy from a shop based outside the UK.

Why Are Grey Imports Cheaper?

Grey imports may be significantly cheaper than UK stock products.
Another factor is that the manufacturer may believe that consumers in Europe are simply prepared to pay more for things, so they make the prices higher than in, for example, Hong Kong.

Import Duty And VAT

If you buy a product from a shop based in Hong Kong, and they send it to you from there, then you may be liable to pay import duty and VAT.
See this page on the HMRC site for details: http://www.hmrc.gov.uk/customs/post/internet.htm

Having to pay VAT on top of the price you have paid the shop, plus import duty and/or handling fees, can make the price of a grey import far less attractive – it is therefore vital to know whether you are importing the product into the UK or not, which means you need to know where it is being sent from.

There are some UK based shops ( Portus Digital is one of these) that import the products themselves from outside the EU, and then sell them to you in the UK. In this case the products should be sent to you from within the UK, and you should not be liable for import duty – and will pay UK VAT on your purchase as normal. As mentioned above, these products can still be cheaper than UK stock, due to the way the manufacturers vary pricing for different parts of the world.
I would highly recommend either of the below retailers:

HDEW Cameras

Portus Digital

I have used both of these retailers, their service and support are  exemplary

How do You Know Its A Grey Import

Whether or not you choose to buy a grey import is a personal choice for you.
The main point for me is that you should have the information to enable you to make an informed choice – knowing the product is a grey import, and whether you will be liable for VAT and import duties in addition.
The problem with many of the grey import shops is that they try very hard to hide from you the fact that they are selling you a grey import. You will normally have to examine their terms and conditions in order to find out about possible VAT and import duty charges, and this is often the only way to work out if they are selling grey imports. Apart from looking for conditions that state you are responsible for import taxes and VAT, also look out for comments saying the products are not eligible for cash back promotions. I’m also cautious when a shop is offering longer warranties than normal – this often is a tactic to hide the fact that you will not get a UK warranty.
In the end though, if the price seems too good to be true compared to the UK prices listed on Camera Price Buster, for instance, then you can assume it is a grey import.

Is It Worth Buying A Grey Import

I am afraid I am a serial offender, it can save so much of your hard earned cash that it would be rude not too !!
But its a personal choice that you must make, weigh up the price saving (taking into account VAT and import duties) against not having a UK warranty. 
And factor in the chance of having to use the warranty based on the type of product. You might feel that you want the reassurance of the UK manufacturer warranty on a £1500 lens, but not on a £50 lens filter which has no moving parts to go wrong.
Just make sure you know what you are getting and where it is being sent from, if it is sent from within the UK then in my opinion its a no brainer.

Camera Price Buster is a great site to find the best prices – but do your own research too.