[lguckert79]

well to start with i love tax season and i am looking at getting either a tamron 28-75mm f2.8 xr lens or a pentax FA 50mm f:1.4. What i need is a good low light lens for portraiture but i have a Pentax-A 50mm f:2 and what i was thinking is that the zoom would be more for my money. i just need some other opition than mine and my wifes thanks

i was also considering a 85mm manual lens one of the new ones with the A pin

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Last edited by lguckert79; 02-01-2012 at 03:40 PM.

[baro-nite]

The A50/2 isn't bad for low-light portraiture (I'm assuming you are shooting with a DSLR, not film), so it would help to know in what ways it isn't filling the bill for you.

A zoom is certainly more focal lengths for the money, but it's less speed.

The Samyang/Vivitar/etc. 85 looks like a good option also, if you like that focal length.

Then again, maybe what you need is off-camera flash?

[DaveHolmes]

I have the 17-50 2.8 tamron lens and it's very good... I barely use it...

My FA50 1.4 on the other hand sees lots of use...

[lguckert79]

i think you are right i might want to upgrade my lighting, because all i have is a very old sunpak flash and i never used off-camera flash i might look in to a better flash

[calsan]

The FA50 is good in low light - in THEORY! The fact is at f1.4 the pictures are really soft and it's a real lottery to get your subject in focus. I also vote for "Get a flash instead!"

[RioRico]

Very fast lenses like the FA50/1.4 *are* sharp wide-open -- but only in a thin DOF zone. We don't use such lenses for edge-to-edge flatfield sharpness. We use these to grab shots that would otherwise be impossible. They are also very sharp when stopped-down slightly.

A fast midrange zoom gives you lots of flexibility. I haven't found a need for such; I use fast primes. Your mileage may vary.

[DaveHolmes]

lenses like the FA50/1.4 *are* sharp wide-open

Agreed... Especially since I put a hood on it...

[brofkand]

The Vivitar 85mm f/1.4 is a very good lens, and less than $300 new on B&H. I feel like a broken record constantly touting this lens, but it really is a stunning lens. Sharp as a tack once you get the hang of focusing at f/1.4. It's really difficult to see in the viewfinder if you're in focus or not.

[lguckert79]

anyone use the *55mm f1.4 because i hear its fov is made for FF so it would view like an 82.5mm lens now is this true or is it made for the sensor

[sterretje]

Forget about that FOV. It's the same as the kit lens at 55mm (and nearly the same as your 50/2).

[RioRico]

anyone use the *55mm f1.4 because i hear its fov is made for FF so it would view like an 82.5mm lens now is this true or is it made for the sensor

A lens does not magically change focal lengths when moved between cameras. A 55mm lens remains a 55mm lens, with the same maximum aperture, not matter where it is. Different size frames 'see' (crop) different amounts of the projected image.

I have a Sigma 24/2.8 lens in T2 mount. With appropriate adapters, I can mount it on a 645D (MF), a K1000 (FF), an Olympus Pen-FT (HF), a K5 or NEX (APS-C), a 4/3 or m4/3 (1/4 of FF size), or a Q (even smaller). The lens remains the same. Its projected image remains the same. Smaller frame crop-away more of the projected image, is all.