Tamron 24mm f/2.4 for 25 bucks

[nickzou]

It was 25 dollars. Got it off a friend, why not. Chump change. Here's the thing, I'm having a hard time focusing this lens at f/2.4. It's a manual focus lens and I can't seem to get it right. If I crank up the f stop, sure I get some nice shots. But not at f/2.4, is there a trick to focusing these lenses? It looks focused in the viewfinder. But apparently it isn't...

 

[dxqcanada]

Some lenses have very poor image quality when shot wide open.

 

[analog.universe]

Manual focusing a fast lens is really tough with the focusing screen that ships with most cameras. Most focusing screens on non-pro cameras are designed for viewfinder brightness and autofocus accuracy, not manual focusing. There are aftermarket screens available that will make manual focusing a no-brainer... in the mean time, one thing I find helps is to watch the position of the focus plane, as you adjust, visualize it moving through the scene. As opposed to watching your subject, and waiting for it to come into focus.

 

[Derrel]

Manual focusing a fast lens is really tough with the focusing screen that ships with most cameras. Most focusing screens on non-pro cameras are designed for viewfinder brightness and autofocus accuracy, not manual focusing. There are aftermarket screens available that will make manual focusing a no-brainer... in the mean time, one thing I find helps is to watch the position of the focus plane, as you adjust, visualize it moving through the scene. As opposed to watching your subject, and waiting for it to come into focus.

^^^^^What he said is pretty much spot-on!!! It might be easier to use the focusing scale on the lens, as long as it's relatively comprehensive, as it typically was on Tamron lenses of that vintage. Focusing by scale is actually reasonably easy if you work at learning a few distances, like 1 meter, 1.5 meters, 2 meters, and 3 meters. Also, while it doesn't make a huge amount of difference on all lenses, on many MF lenses, it is easier to throw the lens out of focus at the Infinity end, and then rapidly rack the lens toward the closer focusing distances, and STOP! as soon as the image "looks good". With, perhaps, a very,very slight hitch, to correct for any over-run. Coming from Infinity inward, to closer ranges, the rate of change is much,much greater than when going the reverse direction, from close to far. Since the human eye can easily spot differences, moving the focusing ring from Infinity toward closest focusing distance, creates the most-rapid changes,and it's a bit easier to spot "out" switching suddenly to "in-focus". What,exactly "looks good" through the viewfinder is what it takes practice to learn to appreciate; with older, manual focus cameras with fully-silvered mirrors and coarser finder screens, manual focusing was easier. Today's mirrors and screens are much more difficult to use to manually establish focus with short focal length lenses like 24mm.

 

[ghache]

just wait until the focus indicator illuminate? i've manually focused with my 50mm before and using the focus indicator the focus was dead on everytime..

 

[nickzou]

Thanks, I got it to focus. Not a great lens by any means but at least I got it working. Appreciate the help.