Advise on new lens
Body: Pentax K-r & K-3 + D-BG5 Battery Grip
Lens: Pentax 18-55mm L - Pentax 18-55mm AL WR - HD PENTAX-DA 15mm F4 - Sigma 18-250mm f/3.5-6.3 DC OS HSM - Sigma 50mm EX DG Macro - Sigma 150-500mm f/5-6.3 DG OS HSM - Kenko 2x Teleplus
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The 120-400 is not really more expensive - it is not as common and the 150-500 at £599 is extremely cheap - the RRP is around £800. The RRP on the 120-400 when I got mine was £799
Carl
No matter how many lenses I have owned - I have always needed just one more
Body: Pentax K-r & K-3 + D-BG5 Battery Grip
Lens: Pentax 18-55mm L - Pentax 18-55mm AL WR - HD PENTAX-DA 15mm F4 - Sigma 18-250mm f/3.5-6.3 DC OS HSM - Sigma 50mm EX DG Macro - Sigma 150-500mm f/5-6.3 DG OS HSM - Kenko 2x Teleplus
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My Flickr link
"Life is what happens to you while you're busy making other plans" (John Lennon)
Body: Pentax K-r & K-3 + D-BG5 Battery Grip
Lens: Pentax 18-55mm L - Pentax 18-55mm AL WR - HD PENTAX-DA 15mm F4 - Sigma 18-250mm f/3.5-6.3 DC OS HSM - Sigma 50mm EX DG Macro - Sigma 150-500mm f/5-6.3 DG OS HSM - Kenko 2x Teleplus
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I have a pretty good macro lens would it be worth getting tubes?
It depends how close you want to get and what magnification you are after. Even a 1:1 Macro lens is not enough for most macro photographers and the best way to get closer without losing IQ is to use tubes or to reverse the lens (which is trickier). Tubes are not easy but can yield spectacular results. Be prepared for fully manual operation (exposure and focussing) unless you spend a lot (£100+) on tubes that maintain automatic functions. I would recommend you buy quality second hand tubes from the likes of FFordes Photography, not the cheap ones on ebay & Amazon as these are absolute rubbish. £15 will get you a quality set of manual tubes.
Regards
David
Flickr
Nicola's Apartments, Kassiopi, Corfu
Some cameras, some lenses, some bits 'n' bobs
Body: Pentax K-r & K-3 + D-BG5 Battery Grip
Lens: Pentax 18-55mm L - Pentax 18-55mm AL WR - HD PENTAX-DA 15mm F4 - Sigma 18-250mm f/3.5-6.3 DC OS HSM - Sigma 50mm EX DG Macro - Sigma 150-500mm f/5-6.3 DG OS HSM - Kenko 2x Teleplus
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David is quite right - your better getting a quality set of tubes (well engineered) and if you are happy to use them fully manually then they can be had for under £20, Auto tubes are dearer. Another method I have read about (but not tried myself) is to buy a cheap PKA converter and remove the glass - this will allow some "auto" functions - to give you a single tube - ffordes often have cheaper 4 element converters for around £15. As I said, I've not tried this myself - but it may be an option.
LennyBloke

Body: Pentax K-r & K-3 + D-BG5 Battery Grip
Lens: Pentax 18-55mm L - Pentax 18-55mm AL WR - HD PENTAX-DA 15mm F4 - Sigma 18-250mm f/3.5-6.3 DC OS HSM - Sigma 50mm EX DG Macro - Sigma 150-500mm f/5-6.3 DG OS HSM - Kenko 2x Teleplus
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Enjoy life

Someone could have told me I needed to go to the gym to use it, it didn't look that big on the website

Can't wait to have a play
Body: Pentax K-r & K-3 + D-BG5 Battery Grip
Lens: Pentax 18-55mm L - Pentax 18-55mm AL WR - HD PENTAX-DA 15mm F4 - Sigma 18-250mm f/3.5-6.3 DC OS HSM - Sigma 50mm EX DG Macro - Sigma 150-500mm f/5-6.3 DG OS HSM - Kenko 2x Teleplus
Flash: AF-360FGZ
Beermonster
Member
Or can anyone recommend a better lens round the £500-700 mark
Body: Pentax K-r & K-3 + D-BG5 Battery Grip
Lens: Pentax 18-55mm L - Pentax 18-55mm AL WR - HD PENTAX-DA 15mm F4 - Sigma 18-250mm f/3.5-6.3 DC OS HSM - Sigma 50mm EX DG Macro - Sigma 150-500mm f/5-6.3 DG OS HSM - Kenko 2x Teleplus
Flash: AF-360FGZ