[straightshooter]

For those of you who have both lenses, is there really that much advantage in the 50 f/1.4 over the 50 f1.7. I'm not talking the FA or anything other than the M and A lenses. I have the 1.7 in both M & A but have been eying some of the 1.4's that have been popping up on e-bay. My thoughts however is that 1/2 stop isn't worth the cost. So is it worth it to buy one or save the money for some other desirable glass.

(Note: I have the Super Multi Coated Takumar 50 1.4 and the M42 adapter if I just had to have that extra bit of light.)

CW

[Gooshin]

its about depth of field, and the fact that some people want less of it. esp at distances of 6-8 feet

[stevebrot]

(Note: I have the Super Multi Coated Takumar 50 1.4 and the M42 adapter if I just had to have that extra bit of light.)

CW

It looks like you have the means to answer your own question. The performance of the M and A versions of the 50/1.4 should be very similar to your tak. The main difference would be coatings (more advanced on the newer lenses), size/weight, and build quality.

Steve

[Nesster]

If you already have the Tak 1.4, you can answer the question yourself

Personally, I'd stick with the Tak, but if I really really had to have another 50, I'd plop for the A as the M really doesn't have any advantage with a digital body.

[Kerrowdown]

1.7 to 1.4 maybe, 1.7 to 1.2 definitely.

[deejjjaaaa]

For those of you who have both lenses, is there really that much advantage in the 50 f/1.4 over the 50 f1.7. I'm not talking the FA or anything other than the M and A lenses. I have the 1.7 in both M & A but have been eying some of the 1.4's that have been popping up on e-bay. My thoughts however is that 1/2 stop isn't worth the cost. So is it worth it to buy one or save the money for some other desirable glass.

(Note: I have the Super Multi Coated Takumar 50 1.4 and the M42 adapter if I just had to have that extra bit of light.)

CW

I think that extra 2 aperture blades ("1.4" has 8 vs "1.7" has 6) makes oof a little bit better... of course it might be because of the different optical scheme too



vs



but I bet 8 vs 6 plays more role

[Frank Fletcher]

I agree with deejjjaaaa (man, that's hard to spell! ... it comes down to the bokeh for me - though I hear that some people think the 1.7 is actually nicer in other respects.

[ChrisA]

All the focusing is done with the lens wide open. So you'd expect to be able to AF reliably in less light with the very fast lenses.

[Marc Sabatella]

All the focusing is done with the lens wide open. So you'd expect to be able to AF reliably in less light with the very fast lenses.

True, but the knock against the 50/1.4 lenses from Pentax has always been that they have relatively less contrast wide open than the 1.7 versions. The 1.4 versions are also rather softer wide open than the 1.7 versions. Both of these are potentially reasons in themselves to prefer the 1.7 versions, but they also affect focusing. Assuming that the 1.7 really *is* sharper and contrastier - I'm just parroting what I've heard other say many times.

Also, note that I'm not saying any of this makes enough of a difference to outweigh the rather obvious advantages of the 1.4 having a wider aperture (in terms of both DOF and shutter speed).

[deejjjaaaa]

All the focusing is done with the lens wide open. So you'd expect to be able to AF reliably in less light with the very fast lenses.

"...I'm not talking the FA or anything other than the M and A lenses...." - so unless he is going to use "catch in/trap" focusing it is not a problem...

[Nesster]

Which brings this nicely back to point: if you have a SMC Tak 1.4, what benefit would you get from a M or A 50 of the same speed? Apart from any possible miniscule difference in optical performance, the only thing I could see is the A gives you full automation with a digital body.

[roentarre]

If you stop down the aperture to f2 most of the time, there is no difference between these two lenses.

As far as the optical design is concerned, they are similar.

[Just1MoreDave]

I would try to answer these questions:

- Can I reliably use manual focus with the lenses I have? If not, you won't use f1.4 because your subject won't be in perfect focus. Might as well stick to f1.7 lenses or try the FA and trust AF.

- How have I used the lenses I already have? This should give you an idea of how much to value A lenses over M, what apertures you favor, etc.

- How critical am I of small details in my photos? If you notice the OOF highlight shape, you might value the extra aperture blades of the f1.4. If contrast or flat field are important, stick with f1.7.

- Where else could I spend the money? The 50s are inexpensive so it's not a huge investment, but a flash or tripod can be useful too.

- Why do I already have 3 50mm lenses? If there's no reason, you can sell them and possibly cover the cost of an f1.4, eliminating cost as a factor.

I have a Super-Multi-Coated Takumar 50/1.4 for its mechanical perfection (rarely used), a Pentax-A 50mm f1.4 for manual focus and low light, and a Pentax-F 50mm f1.7 for its AF convenience. If I was buying today, I'd get the FA 50/1.4, because it's the same optically as the A, only a bit more and new.

[straightshooter]

- Can I reliably use manual focus with the lenses I have? If not, you won't use f1.4 because your subject won't be in perfect focus. Might as well stick to f1.7 lenses or try the FA and trust AF.

Well the eyes are typical for someone 59. I find that I do depend on the focus beep and visual cue when I'm set to manual focus.

- How have I used the lenses I already have? This should give you an idea of how much to value A lenses over M, what apertures you favor, etc.

The M's are used on either MX's or ME's and one A is on my wife's Super Program basically giving her a 35mm SLR P&S. The other A is for my K100D Super so it does have some value for digital work.

- How critical am I of small details in my photos? If you notice the OOF highlight shape, you might value the extra aperture blades of the f1.4. If contrast or flat field are important, stick with f1.7.

I'm not that obsessed with the small stuff in most cases. I do like nice bokeh but it's not the most important thing to me.

- Where else could I spend the money? The 50s are inexpensive so it's not a huge investment, but a flash or tripod can be useful too.

Oh lots of places. Wife's birthday, property tax, etc. LOL

- Why do I already have 3 50mm lenses? If there's no reason, you can sell them and possibly cover the cost of an f1.4, eliminating cost as a factor.

Actually I have several 50's but they're mounted on several different film bodies.

If I was buying today, I'd get the FA 50/1.4, because it's the same optically as the A, only a bit more and new.

Thanks Dave. I think if I do go with a K mount 1.4, it will be the FA 50. Your first point about reliably using using manual focus hit home. Sometimes we just don't want to admit or maybe just don't think about the fact that we aren't 20 years old anymore and things just don't work as well as they did 40 years ago. It's for sure my eyes don't.

CW

[thePiRaTE!!]

I think f1.0 is worth it. F1.4 is a steal. Its just that no one will take my money for an f1.0 in K-mount

To augment the discourse here generally - I would like to clarify that # of blades comes into play by shaping the light once the aperture is engaged and visible in the image (ie, not 1.4). This is seen in highlights: round, hexagons, etc in the shape of your aperture. The blur itself is just blur regardless of aperture blades, thus its really rather a myth that more blades means anything at all to bokeh. Notice during many Hollywood movies, amazing bokeh and often hexagon highlights (for some reason, the new Rambo comes to mind).

f1.4 has the potential to mangle the oof more dramatically than 1.7. If you seek more dramatic isolation of subject vs background, then yes, 1.4 can offer you some advantage.