[Jan in Waterloo]

Hi, my name is Jan. I’ve been a Pentax istDS owner for 3 years. While I have enjoyed this camera, I have had serious issues with its ability to autofocus in low light situations. I have used my sister’s Nikon camera and really enjoy the low light focusing capabilities and her 18-200 VR lens.

I am now considering purchasing a new camera. I have looked at the K10D and really enjoy the features and the quality of the product. I am curious to know what owners of this camera think of the low light focusing abilities. My other concern is that Pentax does not offer an 18-200 mm lens, so my only options will be either a Tamron or Sigma lens. I would appreciate your comments on which of these 2 lenses people prefer and your issues with them.

I have enjoyed reading Forum members’ reviews of various products and look forward to any and all replies regarding my questions. Thanks!

Jan in Waterloo

[Dr_Watso]

Hi, my name is Jan. I’ve been a Pentax istDS owner for 3 years. While I have enjoyed this camera, I have had serious issues with its ability to autofocus in low light situations. I have used my sister’s Nikon camera and really enjoy the low light focusing capabilities and her 18-200 VR lens.

I am now considering purchasing a new camera. I have looked at the K10D and really enjoy the features and the quality of the product. I am curious to know what owners of this camera think of the low light focusing abilities. My other concern is that Pentax does not offer an 18-200 mm lens, so my only options will be either a Tamron or Sigma lens. I would appreciate your comments on which of these 2 lenses people prefer and your issues with them.

I have enjoyed reading Forum members’ reviews of various products and look forward to any and all replies regarding my questions. Thanks!

Jan in Waterloo

Pentax actually has a new lens with a range of 18-250.

[Confused]

Hi Dr_Watso

With due respect, when you naively stated to Jan that:

Pentax actually has a new lens with a range of 18-250.

....you really ought to have 'qualified' that statement a little ! I'll have you know, I nearly blew the froth off my coffee......
and I don't even drink the stuff !
What Pentax 'actually has' on offer is what could kindly be termed as a 'rebadged' Tamron 18-250mm Di II. It's a stop-gap measure in an attempt to plug a gaping hole in their currently ill-equipped lens line-up. Just in case you're wondering I'm not trying to bash Pentax unduly, as I own the Tamron myself and am pretty delighted with it overall. I simply had to straighten matters out somewhat for others reading this post,

Best regards
Richard

[Snowcat]

Jan in Waterloo, I own GX-10 for a quite little amount of time, but i was able to shoot a Halloween party, i had with my frieds. We were in a room lighted only by some candles, and in such condition, using kit lens (18-55) i had no problems with autofocus, except when i tried to focus on a girl, who was in a completely black blouse, but similar problems had Canon 350D, Sony A100 and Nikon D50 (yep, ALOT of my frieds are photomaniacs lol).
Don't know how 18-250 will focus in such conditions though...

[clawhammer]

The ease of low-light focusing has to do with the maximum aperture of the lens, because the smaller the aperture, the less light getting to the AF sensors. Thus, a lens with an aperture of f/2.8 will focus easier than a lens with an aperture of f/5.6 because there is a lot more light getting to the AF sensors. Based on this, I would imagine that the Nikon would do better at low-light because it is a f/3.5-5.6 (meaning once you zoom out it has a maximum aperture of f/5.6) verses the pentax/tamron/sigma superzooms that go to f/6.3 at the long end. Granted, you probably won't see much difference at those small apertures. The best thing you can do for low-light photography is to use an external flash, like the AF360 for Pentax or SB-600 for Nikon that fires a near-infrared assist beam to give the AF system something to latch on to.

[MUD]

Jan -

A couple of ideas......

Set auto-focus to single servo, not continuous - once focus is attained, you're locked.

In low light situations, set your focus selector to "center" or at the least "select", if your subject is off center. If camera is set to multi-segment focusing, especially in low light, the lens will have no idea what it is/you are looking for, hence hunting.

Additionally, try to find areas of contrast to focus on. In snowcats example with the girl in a black blouse, I would be centering my focal point on say, the black blouse and neck line or maybe the girls forehead and hat (if she was wearing one), lock focus, recompose and shoot.

All the best -

Jonathan

[stewart_photo]

(snip) What Pentax 'actually has' on offer is what could kindly be termed as a 'rebadged' Tamron 18-250mm Di II. It's a stop-gap measure in an attempt to plug a gaping hole in their currently ill-equipped lens line-up. Just in case you're wondering I'm not trying to bash Pentax unduly, as I own the Tamron myself and am pretty delighted with it overall. I simply had to straighten matters out somewhat for others reading this post,

Why would mentioning the lens manufacturer be bashing Pentax, Richard? A good number of the lenses sold by nearly every camera company (Pentax, Nikon, Canon, Sony, etc) are rebranded lenses manufactured by another company. It is far more cost effective, and therefore wiser from a business perspective, for camera companies to do this than build a nearly identical lens to that already made by someone else.

Canon and Nikon, both larger companies with more marketing clout, are usually able to gain exclusive rights to a particular lens (meaning only one or the other, and not the original manufacturer, can sell that lens), while smaller Pentax often obtains shared rights (meaning both Pentax and the manufacturer Tamron, in the case, can sell the same lens under their own names). However, the agreement with Pentax usually prevents another camera company, such as Canon or Nikon, from gaining access to sell that particular lens (often exclusive access, meaning we Pentax users can't have it).

stewart

[WMBP]

What Pentax 'actually has' on offer is what could kindly be termed as a 'rebadged' Tamron 18-250mm Di II. ...

Richard,

Do we actually know this? I have heard it claimed repeatedly and it sounds reasonable, but I have not seen anything that says this explicitly. And is this Pentax-branded lens available for purchase yet? I don't think I've seen anybody here mention that they actually had one.

Like you, I had the Tamron 18-250 and it's a very decent lens. Its predecessor, the Tamron 18-200, is still available for purchase and is about $100 cheaper than the 18-250. The 18-200 is also a decent lens, perhaps not quite as good as the 18-250, but I owned 'em both and didn't see a huge improvement in image quality when I upgraded to the newer, longer lens.

To the original poster: 18-200 is a nice range for a zoom lens, if it's a decent quality product. I sold my Tamron 18-200 a while ago to upgrade to the Tamron 18-250, then sold that because I realized I wasn't using it. I tend nowadays to use lenses with a more limited range depending on what I want to shoot. But if you can have only one lens and you want to keep your options open for all kinds of shots, then the 18-200 range is just about perfect. In addition to my Pentax digital cameras, I shoot with a Nikon N65 film SLR for which I have just one lens: a Nikkor 18-200. Works quite nicely as an all-purpose lens.

Will