Other possibilities to consider in Kent:

link

link

link

and in Greater London but within striking distance of Bromley:

link

link

link

Bonne chance,

Jon

Another option worth considering would be a second-hand Tamron 2X Pz-AF BBAR MC7. I had the good fortune to obtain one recently as part of a 'job lot' with an immaculate Sigma 400mm f/5.6 (non-APO)and 35mm Z10 body with SMC Pentax FA 28-80mm f/3.5-4.5 (£127.00 the lot :twisted.

It works well with the Sigma 400mm and my Sigma 100-300 f/4.0, as this recent test shot (K20D at f/4.0; cropped) shows:

[img]http://farm8.staticflickr.com/7006/6629090803_ee2827635a_b.jpg" class="comment_image" />

Sigma 100-300 f/4.0 EX DG plus Tamron 2X Pz-AF BBAR MC7 by Dr 'B ', on Flickr[/img]

In good light, AF is possible, but slow with a degree of 'hunting' on both lenses (100-300 f/4.0 < 400 f/5.6), but my preference when using the TC is MF. Should prove more reliable/consistent with the 70-200 f/2.8.

Don't have a lens with SDM so I can't comment, but others have reported variable degrees of success dependent on the lens used (search on the forum at the 'other place').

Jon

Lens now sold to Qing (summerHex).

Many thanks for a smooth and pleasant transaction.

Enjoy the lens and the pleasure of wresting back a degree of control from the camera electronics

Jon

Fine example of this sharp little lens in excellent condition (functional and cosmetic). Front and rear elements are unmarked and, unusually for a lens of this vintage, there is very little evidence of dust particles internally. Focussing and aperture rings work as they should, as does the lens aperture itself. Capable of producing sharp images with good contrast and colour rendition even when combined (as shown below) with a 2X macro-converter.

[img]http://farm8.staticflickr.com/7172/6549065199_4e7c598be2_b.jpg" class="comment_image" />

Front by Dr 'B ', on Flickr[/img]

[img]http://farm8.staticflickr.com/7024/6549066249_544871109e_b.jpg" class="comment_image" />

Rear by Dr 'B ', on Flickr[/img]

[img]http://farm8.staticflickr.com/7162/6549067085_8f3e3f4a75_b.jpg" class="comment_image" />

SMC-M_50mm@f4 by Dr 'B ', on Flickr[/img]

£30.00 including original lens cap, third-party rear cap and delivery in the U.K.Prospective oversea buyers please PM for shipping options/costs. Payment by bank transfer or PayPal (buyer pays fees).

Jon

Hidden in Plain Sight, by Paul L. Richman, Ph. D.

Well written and illustrated, informative article full of useful tips that cover the entire process of dragonfly photography from image capture to post-processing published this month on The Luminous Landscape site link

Jon

All worthy captures but, for me, the first reigns supreme with its 'spot on' exposure, hue and saturation and arresting combination of foreground detail in the spider and seed offset by the muted colours and shapes present in the out-of-focus background

Am I right in thinking that orb spiders are capable of giving a nasty bite with sufficient venom (:lol to cause several hours of pain and discomfort?

Jon

Johan, I am serious in so far as the original topic of conversation was the article posted on the Guardian website entitled: "Cameras and kit: best buys for wildlife photographers: We turn our focus on the best-value digital cameras and equipment to help capture that perfect wildlife shot" and the advice given therein to "amateur wildlife photographers wanting a "start-up" kit (my italics), which, IMHO and as I stated in the comments section for the article, was a classic example of 'lazy journalism'.

In the broader context, I have no issue with the general thrust of your argument. Indeed, I would not hesitate to switch systems if the time came when my interests had developed and become specialised to the extent that Pentax and the independent manufacturers of lenses, flashes and other photographic tools were no longer capable of meeting my needs.

For the present, however, my own photographic limitations far outweigh any that might result from my having invested in a Pentax based camera system

Best wishes,

Jon

I don't think worries about SDM failures should deter potential buyers as there are now 'tried and tested' DIY fixes available that cater for all levels of technical expertise.

link(scroll down to the post for 13/10/2011) and link

Jon

I am perturbed and puzzled in equal measure by your statement and those in a similar vein posted in this thread and wonder when you last looked through the gallery and the 'Your photos' and 'Competition' section of the forum on this and other sites devoted to those who have chosen to use Pentax equipment (alone or in combination with lenses from the likes of Sigma and Tamron)), which collectively provide an overwhelming body of evidence to refute your contention?

I accept that, with their extensive ranges, the likes of Nikon and Canon are able to provide a 'one stop solution' for those with monotheistic tendencies as far as photography is concerned but, when all is said and done, patience and an in-depth understanding of the natural history of the chosen subject is of far greater importance than the brand of equipment used.

Jon

I posses a range of polarisers of different size from Hoya, Sigma, Marumi and Kenko and I can't say I've noticed any great difference between them in terms of how difficult they are to rotate.

Jon