Search results for 'back focus' - page 1154
Lens conundrum
aren't zoom lenses varifocal lenses? They can be, but can be parfocal too. Varifocal lenses need refocusing when zooming, parfocal lenses keep the same focus at different focal lengths.
Posted by petrochemist on 10/03/2015 - 19:30
Lens conundrum
Even a prime macro lens may change focal length when focusing close, especially internal focus designs.
Posted by johnriley on 10/03/2015 - 19:34
Cosina PK ' Pentax PK Fit 24mm 2.8 Prime
Cosina used to make all kinds of PK lenses and then place different names onto them. Back in the 80's Cosina sold more PK lenses than even Pentax. One of their larger names that was added to the front lens barrels was the North american name (borrowed from/added in?) from Ritz Camera - the Quantaray...
Posted by 50mpCMOS on 14/03/2015 - 21:49
400mm lens
I have heard good a bad things about Sigma 400mm primes and personally would look for the tokina/hoya versions - I did buy one but sent it back as it was full of fungus :shock: I have an m42 NPS 400mm which is rare and takes a bit of work but I have had decent results with it:D The Tokina one ...
Posted by Stuey on 15/03/2015 - 19:48
400mm lens
Sorry guys, its currently sat next to me on my K5IIs at work waiting for something to come along worth shooting!!!:D At the moment I'm spending far too much time at work, on the smallholding or fishing....:( On the few test pics I took with the K3 it doesn't seem to be as sharp as the DA* 300, b...
Posted by andy_bell on 18/03/2015 - 08:32
Heads up... Mega Pentax Lens deals next weekend
Hi everyone. As promised, please see below prices which we will be offering over this weekend. These prices will go live at 12.01am tomorrow morning. However! If anyone wants to order from the forum today, we can accommodate this and if ordered before 4pm the items will go out for deliv...
Posted by Chris@SRSWATFORD on 26/03/2015 - 10:17
Heads up... Mega Pentax Lens deals next weekend
i was very tempted to go for the da 300 star but im worried about sdm failures I own the 16-50, 50-135, 60-250 SDM lenses and have done over 2 years plus. I am a second owner of the 16-50mm and the documentation it came with indicates that it has had AF circuity and SDM replaced but the lens also sh...
Posted by George Lazarette on 29/03/2015 - 11:50
Heads up... Mega Pentax Lens deals next weekend
I also own two Sigma HSM lenses. Both of which have been repaired outside of warranty for AF faults. (Looking at the paperwork for the 16-50, the cost of the repair was about 2/3 of what its has cost me to get the 50-500mm sigma AF circuit repaired) Interesting you should say that, both my Sigma 50-...
Posted by Mike-P on 29/03/2015 - 12:47
Lens Upgrade Choices
The 50-135 is a very very lovely lens. It's so handy having the constant f2.8. The Tamron 17-50 would complement it well, so I would persevere with that one... maybe try calibrating the focus? I found mine was slightly backfocusing but it's fine now. The 16-85mm is tempting though, I'll give you ...
Posted by Pentaxophile on 25/03/2015 - 08:42
Comparison of 16-50 and 16-85
Obviously there is no need to point out that one has a longer range! :-) Thanks G That's me out then. :roll: Welcome back George ... a passing visit or are you staying a while ? :D
Posted by Mike-P on 25/03/2015 - 12:10
Comparison of 16-50 and 16-85
Obviously there is no need to point out that one has a longer range! :-) Thanks G That's me out then. :roll: Welcome back George ... a passing visit or are you staying a while ? :D Well, I think I might stick around. Pentax is definitely moving forward more rapidly under Ricoh than it did...
Posted by George Lazarette on 25/03/2015 - 12:38
Comparison of 16-50 and 16-85
Good to see you around again George :D Good to see you are still here! G And another welcome back from me George :-)
Posted by McBrian on 25/03/2015 - 20:18
Comparison of 16-50 and 16-85
[quote:3496ace15f="Stuey"]Good to see you around again George :D Good to see you are still here! G And another welcome back from me George :-)[/quote] Very kind of you! Cheers G
Posted by George Lazarette on 25/03/2015 - 20:23
Comparison of 16-50 and 16-85
Hello again George. I love my 16-50, well perhaps love is a bit strong for an inanimate object. It works well for me, just occasionally a tad heavy when on the hills for a full day. It's understandable that those who have experienced a focus motor issue are wary of the lens, but those who haven'...
Posted by George Lazarette on 25/03/2015 - 21:33
Comparison of 16-50 and 16-85
Hello again George. I love my 16-50, well perhaps love is a bit strong for an inanimate object. It works well for me, just occasionally a tad heavy when on the hills for a full day. It's understandable that those who have experienced a focus motor issue are wary of the lens, but those who haven'...
Posted by jules on 31/03/2015 - 17:20
Comparison of 16-50 and 16-85
I am in the same position as you George, looking for a wide zoom to take with on holidays. The DA* from a user review perspective is hampered by mainly 3 things, a: SDM failure, b: price, c: it has a QA related character. Price is set by the idiots running the global financials, value of whateve...
Posted by robbiec on 11/04/2015 - 11:51
Old vs New
I have posted quite a few photos recently using the old smc m lenses. My question is apart from the camera metering and more focus points being available when using the newer models. Is it worth investing in more modern day lenses. Considering I am more than happy with the IQ on all lenses in my ba...
Posted by philstaff on 25/03/2015 - 14:17
Old vs New
I caught the lens bug through not knowing which was what was good or bad, so I bought them off E bay for comparison and sold what I didn't like. I expected to end up with a very few modern automatic ones but I now have a fantastic collection of manual Takumars, Helios and Jupiters - DO try the Russi...
Posted by davidwozhere on 25/03/2015 - 23:45
Getting rid of the yellow in Tak lenses; fungus in any lens?
There's plenty of UV in sunlight too! The standard way of getting rid of the yellow colouration with sunlight involves leaving the lens on a windowsill with some aluminium foil on the back element (so that the light gets a double pass). It's very effective, but I always wondered whether the heating ...
Posted by Cuchulainn on 30/03/2015 - 14:16
AF problem on Pentax 18-135
I recently acquired a 18 - 135mm Pentax lens as a walk about lens. There seems to be a problem with the AF It won't auto focus when used between 18 and 35mm. Above that it is fine. I have two K5 bodies and it has the same problem with both bodies so I have to assume that the lens is at fault. I ha...
Posted by DigitalKitchen on 29/03/2015 - 07:07
