[butterworthtom]

I got a Sony A380 as a Christmas present, and having taken afew pics I am finding I can't get my photos in perfect focus. I am thinking perhaps this is down to the kit lens that is on the camera (Obviously not my abilities).
I was looking at this lens:
http://www.amazon.co.uk/Sony-50mm-1-8-SAM-SAL-50F18/dp/B002CQB4J6

I figure a prime lens might be a good investment as I have legs which I can use instead of a zoom.

Do you think this would be a good investment? Would it be good for bouldering photography? And portraits?

[tomtom]

Loads of people on herer will know more, but for bouldering pics I find a wide angle (I've got Daves old 10-20mm) the best. I got my old man a 50mm prime for Xmas and the main trick that allowed (so it seemed to me) was to beable to do loads of depth of field tricks at max apature - which made it really good for portraits.. not sure how well that would work with bouldering/climing...
 

[Paul B]

does the camera have micro adjustment? If so you might be able to easily fix it.

Have you tested the focus (you can print off a chart that you focus on the line and it'll show you if its front or back focussing consistently)..

It might also be worth checking if its a specific AF point, a pesky spec of dust could be causing one point to flake out (tests I've seen have shown the actual locations of the AF points to not always be exact on the markers!). A general clean couldn't hurt, especially if its been near chalk?

If its new and its doing either of these things it could be that your lense/camera combination sit at either end of the manufacturing tolerances and need adjusting to play together nicely. Nobody is ever going to tell you that a 50mm is a bad investment but another lense not working properly isn't the correct reason to go out shopping for a new one (when said lense is under warranty).

[Johnny Brown]

Its highly unlikely that a modern camera and kit lens aren't capable of giving you a sharp picture - there are plenty of other factors which might be the problem even before the hardware issues Paul suggests. Can you post an example?

[butterworthtom]

I was slightly exaggerating the focussing problem, chalk and grime have not yet been anywhere near my camera. It seems very capable of focussing at certain ranges. It isnt too hot at focussing at its maximum focal range (55mm). Also I would quite like to have a faster lens as the maximum aperture at 55mm is f5.

I was just thinking I could get an even better sharpness with a prime lens?
It's probably just a case of being a gear junky.

[Paul B]

It's probably just a case of being a gear junky.

I know this feeling. Its expensive.

With re: to dirt and grime; many of the new Nikon D7000's had lense communication problems and all sorts due to oxide layers forming on contacts between production and delivery, it might be worth a look anyway just to make sure.

BUT

Is it definately a focussing thing then and not something else? Zoom lenses are built as compromises from what I understand and thus their optical performance ranges on focal length & aperture. Somewhere in the midrange will likely offer the best performance.

As primes don't have to make as many compromises they're quite often optically better (again from what I understand). Be a gear junky and go and pixel peep at some reviews. My 50mm is quite soft edge to edge wide open but as soon as its stopped down its incredibly sharp. The more expensive version is slightly better etc. The really expensive version isn't actually meant to be that great.

[butterworthtom]

Are you using a Sony lens then Paul?

For short to middle focal ranges I do not have any issues with focus on the kit lens, but I do at longer focal lengths (up to 55mm). That is why I was thinking of a 50mm Prime, I read from various reviews that for the price it is a very good lens.

[Paul B]

Are you using a Sony lens then Paul?

No, Canon. Queer hotshoe would have really p*ssed me off by now. I did like the idea of body based IS though.

I think all manufacturers do a "nifty 50" which is excellent for the money. Despite this I still can't see why you should accept dodgy focussing on the other lense, have you seen if this is a common problem?

[butterworthtom]

I have just looked at a website showing some interactive graphs with focus, and it does indeed show slightly reduced focussing capabilities at maximum focal range, although according to the analysis that the author makes it isn't that bad.

[butterworthtom]

What's this hotshoe problem btw?

[Paul B]

What's this hotshoe problem btw?

It shares a footprint with Minolta and isn't standard thus you must buy sony gear or use adapters for them to use third party products, leads etc. Its not so much of a problem, more of a feature.

[SA Chris]

Why do I have it in my mind that Pentax lenses can be used on Sony DSLRs?

If this is the case, I think have a Pentax 50mm prime lense you can have / have a play with and return sometime. I bought an Old ME Super SLR on flea bay a while back, and it had this lens mounted on it, and I still have an identical lense from my original ME Super. It's Manual Focus though.

[slackline]

Pentax K-mount doesn't mention Sony (other than mounts/adapters), and Sony is originally based on Minolta.

[SA Chris]

Must be trippin' then.

[Johnny Brown]

It isnt too hot at focussing at its maximum focal range (55mm). Also I would quite like to have a faster lens as the maximum aperture at 55mm is f5.

I was just thinking I could get an even better sharpness with a prime lens?

That makes more sense now. Part of what we perceive as 'sharpness' is the degree to which the focussed subject is distinguished from stuff in front or behind. Yes a faster lens will give you that, by blurring closer and further objects more - ie decreasing the 'depth of field'. You can also achieve that with a longer lens - if I had a standard zoom I'd be tempted to get a lens that increased range rather than just speed, but that's up to you.

A 50/1.8 or similar will certainly be a breath of fresh air compared to a cheap standard zoom. The bigger aperture gets you a lot more besides less DoF - brighter viewfinder image, faster AF, faster shutter speeds and or lower ISOs. There's also something very engaging about using a prime - you can't zoom so have to do the work on framing yourself. Its great discipline when you're learning.

As primes don't have to make as many compromises they're quite often optically better (again from what I understand).

Although this should be true from a commonsense standpoint, it isn't really nowadays. Prime lenses got about as sharp as they were going to get 20 years or so back, and manufacturers have since concentrated on improving zoom peformance. For example the sharpest lenses in the 20mm range are either the latest Nikon zooms or or old Contax/ Leica MF primes. The best rule of thumb nowadays is that sharpness is more closely related to cost (unless you're keen for old manual primes on adaptors).

[butterworthtom]

Thanks for all the replies, and the offer of borrowing a prime lens, SA Chris.
I figure I will leave it for a bit till I can improve a bit, I think I would like to try some prime lenses out  Does anyone know of a photography shop that will let me do this?

[Paul B]

Harrisons?