Originally posted by dougfrey I understand that the K5 will allow much higher ISO, but I am thinking that a higher quality lens will give me much more sharper images. For low light situations, will faster lens or higher ISO give me better quality pictures?
While the Later cameras, K20, K7 and K5 all have better high ISO and higher resolution sensors than the K10D, I would need to look and think hard and long about the benefits and trade offs.
It almost would be a fun challenge, considering I have the K10D, K7D and K5D (I am a hoarder and never sell anything), to see the gains made going from a kit lens to faster lenses. My gut feel is that there are the following things that a lens will gain you that high ISO will not.
- better low light AF perfromance because the more light into the AF sensor the better
- better sharpness at any aperture, because the kit lens is F4-5.6 and I am sure a 50mm F1.4 is much much sharper at F5.6 than the kit lens is wide open
- brighter viewfinder
- more creative control of depth of field that only a prime can offer.
the only time I would potentially consider going K5D over K10D is if you are where I am right now. I shoot wildlife for a hobby. The High ISO performance of the K5D (and even the K7 before that) are making me reconsider the need for any faster long glass. Considering right now I have a 300F4 (which I add my 1,7x AF TC to get 500mmF6.7) and 70-200F2.8 lenses which I add 1.4x and 2x TCs to get 400F5.6, for me the next step up in fast long AF lenses is a $3000 step. The K5D over K10D really makes a difference there, but that difference goes down with shorter focal lengths. Also, I am already sitting on "prosumer" lenses not kit stuff, so I have already made a step similar to what you are considering.
Go for the glass first, The fact is, even old glass can perform very well on newer cameras when you get around to updating.