[GibbyTheMole]

How do you rate the Pentax-M 50 mm f1.4 compare to the 1.7

I have the A1.7 & the M1.4. They're both equally stellar performers, as far as I can tell. I don't think the 1.7 offers improved IQ over the 1.4, as far as I can see. Only reason I have both is that I bought the 1.4 first, and the "A" 1.7 happened to pop up virtually free & I wanted a version with the "A" contacts. The build quality on the "M" version is nicer, though.

[Bayside Graphics]

How do you rate the Pentax-M 50 mm f1.4 compare to the 1.7? I have the first, and I wonder if there is any benefit in looking for the more popular f1.7 version.

Not sure yet as it has been MANY years since I used such a lens, however, I have read (and someone can correct me if mistaken) that the 1.7 gets better results when stopped down to 2.8. Reading posts in the Pentax lens forum reviews there is a definite "quality" distinction with the 1.7 in that many more users have regarded it as superior. I suppose it all depends on the user, the light available and the shot you need!! Since maost of my work will be without flash... I am still tilting to the M 1.7 version and pick up an "A" for flash use. We'll See...

[JimJohnson]

If you are the type that absolutely loves doing everything manually, it really won't matter if you have the M-series or the A-series 50mm f/1.7; you can use either lens the same way. However, if you want the most flexibility and functionality with your Pentax digital camera, A-series wins this contest hands down.

[timo]

How do you rate the Pentax-M 50 mm f1.4 compare to the 1.7? I have the first, and I wonder if there is any benefit in looking for the more popular f1.7 version.

The conventional wisdom on this forum is that the 1.7 is great and the 1.4 is less so - that's not my experience. The 1.4 lacks a bit of contrast at 1.4 compared to the 1.7 at 1.7, and it is crucial (and difficult) to get the focus spot-on. But the detail is there. Upwards of 2.0 I don't think there is any material difference between them, except that my 1.4 is slightly better at the edges and corners than the 1-7 when stopped down a bit and used for landscape or architecture. They say that the 1.4 has better bokeh. A bit softer maybe but not worth agonising about. They're both fine lenses, basically.

Whichever you have - 1.7 or 1.4 - I just don't think getting the other one is worth the effort and postage costs.

(I have M 1.4 and M 1.7, and an FA 1.7; I used to have an FA 1.4)

Tim

[Bayside Graphics]

How do you rate the Pentax-M 50 mm f1.4 compare to the 1.7? I have the first, and I wonder if there is any benefit in looking for the more popular f1.7 version.

From my old film days I would think the 1.4 might be have an edge based on speed and sharpness (even if you have to stop down 1 you have the edge) but for price and general use, I really think my first purchase choice will be an M 50mm 1.7 (rather than the "A" after all this discussion. It's said that there is a learning curve with the buying of lenses. Use one...if you like the results, stick with it. If there are constant issues that bother you, change it for one that corrects that issue. Personally if I were you I'd keep the 1.4 for sure!

BTW...I also LOVE the quality of construction of the "M" over the "A" and I think to me that makes a real difference. TMHO!

[kh1234567890]

How do you rate the Pentax-M 50 mm f1.4 compare to the 1.7? I have the first, and I wonder if there is any benefit in looking for the more popular f1.7 version.

The M1.4 is better until about f/5.6, then the A1.7 is possibly slightly better, but there is not much in it. The only reason to get the A1.7 as well would be if want the automatic aperture. But then you get that horrible plastic aperture ring which is best set at A and forgotten

I have some completely non-scientific test shots taken purely for my own amusement (before anyone whinges about them not being taken under the same carefully controlled weather conditions, as someone did on 'the other' forum) - Pentax A 50mm f1.7 - a set on Flickr and SMC Pentax M 50mm f1.4 - a set on Flickr.

[stevebrot]

I also own them both and they are equivalent optically. In regards to build, there is NO comparison. The M 50/1.7 is a precision-made and sturdy gem. The A 50/1.7, on the other hand is plastic and not very nice plastic at that. In addition, the aperture ring mechanism on the A 50/1.7 is fragile. I don't believe that I have seen a copy where it was not at least partially broken. This is not a huge issue, unless you decide at some point to use the lens with a bellows or extension tubes or on an older film camera.

So what about real-world use? As I said, I own both lenses in addition to a ton of other fast 50s. The A 50/1.7 is currently mounted to my Pentax Super Program and that is where it pretty much stays despite the convenience factor. It is quite realistically my least favorite fast 50 mounted on what is probably my least favorite camera! It is simply not as pleasant to use as my other lenses.

Bottom line is that I would not pay a premium price for the A 50/1.7. (At least, not again...I gave just over $100 USD for mine back in 2007 during the post-K10D K-mount buying frenzy!) If you want a (slight) quality upgrade from your M 50/1.4, you might want to consider the K 55/1.8 or SMC Takumar 55/1.8. Both are better (IMHO) than either the A 50/1.7 or M 50/1.7 and the Tak is VERY compact.


Steve

(...apologies to fans of the Super Program. It is a decent camera with a great feature set, but it has never resonated with me...)

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Last edited by stevebrot; 11-30-2012 at 09:31 PM.

[pacerr]

Like many others here, after half a century of Pentax-ing I've accumulated the M 50/1.4 & /1.7, the Super Tak 55/1.8 & /2.0 and the A 50/1.7 & /2.0. My favorites are the M 50/1.7 and the ST 55/1.8 for pure pleasure of use and consistently great results.

Given the type of photography I'd do with flash and 50mm lenses I'd be just as happy using one of the modern digital lenses in the 50mm range as with one of the SMC A lenses and see no advantage in the older lenses for that purpose.

When using the older 50's with flash and/or extension tubes, it's really no more trouble to use the M- or M42-class lenses than it is to use the A-class lenses.

If I were to keep only one of those six non-AF lenses, it would be the M 50/1.4 simply because it offers a choice of rendering and available light speed at F1.4-2.0 that I can't achieve with any of my modern DSLR lenses. Aside from that 'unemotional' rationalization, the M 50/1.7 is still the one that brings out the biggest smile when used.

If an SMC A 50 is wanted for flash use only, consider a $20 A 50/2.0 -- for the typical flash shot at F 4 - 11 that lens will will deliver results you won't be able to distinguish from any of the others.

* In every case, habitual use of a lens hood with any of those lenses will make a noticeable improvement in contrast and apparent sharpness for 80-percent of your shots.

H2

[kh1234567890]

* In every case, habitual use of a lens hood with any of those lenses will make a noticeable improvement in contrast and apparent sharpness for 80-percent of your shots.
H2

That is a very good point, especially as on APS sensor and with the lens wide open there is a lot of stray light bouncing around inside the camera. A deep hood does really help.

[Schmidlapper]

Here are links to some well controlled comparison shots i took using the lenses you have mentioned.
Center Sharpness wide open: 50mm wide open test - a set on Flickr
Center Sharpness @ f/5.6 50mm @f5.6 test - a set on Flickr
I still fluctuate between all of them because they are so close. M1.7 did seem to be sharpest wide open with the rest close.

[Naruto]

Here are links to some well controlled comparison shots i took using the lenses you have mentioned.
Center Sharpness wide open: 50mm wide open test - a set on Flickr
Center Sharpness @ f/5.6 50mm @f5.6 test - a set on Flickr
I still fluctuate between all of them because they are so close. M1.7 did seem to be sharpest wide open with the rest close.

I am not sure that it is fair to compare two Pentax-M 50 mm lenses, one at 1.4 and the other at 1.7. IMHO it makes better sense to close the 1.4 to 1.7 and then proceed.
These two lenses look very much the same at 5.6, and seem to have a different contrast from the A.

[Schmidlapper]

It is not unusual to compare the wide open performance of a group of lenses and then progress to comparing the in common ones. I tested them at several apertures, I just don't have them all on Flickr. I did upload 5.6 and 8.0 as they were common to the most in the group tested. On the M50 f/1.4 the next stop is 2.0 not 1.7 so even if the 1.4 is sharper at 2.0 my copy of the 1.7 is sharper wider open. The first common aperture tested is f/2.8, and by then it is starting to be hard to decern a big difference.

[abacus07]

In the end the difference between some M and A lenses (some are optical copies) is price and aperture control (inc. exif info). Whether or not the 50-100% price premium is worth it is up to you. I have one Pentax A lens (50f1.7 - my first legacy lens) and I think 8 Pentax M/K lenses. That's mostly due to bargain shopping on Ebay and not willing to pay the higher prices of A's. However I will definitely sell my M50f1.7 before/soon and keep the A50f1.7 because the A contacts are worth it to me.

Regarding the difference the 50f1.4 and the 50f1.7: I don't see any reason to own both unless you are a collector or you are trying to get the last 1% out of your photos. The one difference that is easy to see is the Pentax A50f1.7 produces a 6 sided star vs an 8 sided star (50f1.4) when shined at a bright light source. I don't have a 50f1.4 but the star is just as sharp but obviously 8 sided. The 55f1.8 is similar to the 50f1.7 in this respect but my copy (takumar) doesn't produce as sharp of a star.

A50f1.7

[Schmidlapper]

one difference that is easy to see is the Pentax A50f1.7 produces a 6 sided star vs an 8 sided star (50f1.4)

This is very true. I have done other kinds of controlled tests and for three dimensional objects the M50 f1.4 looks every bit as sharp wide open as the 1.7s (samples provided below). This demonstrates that a resolution chart doesn't always tell the whole story. And as you mention the 8 blade aperture makes circular bokeh rings up to f5.6, while the six blades were plainly six sided objects by 2.8.
M50/1.4 @ f1.4

M50/1.7 @ f1.7

A50/1.7 @ f1.7

[sunglint]

Coming from the film world I prefer wide-open metering and composure. Since it takes an A or newer to link the aperture I try to go with those where possible. I have a 50 M 1.4 and will use it for night handheld stuff where it's going to stay open, but find my 50 A 1.7 to be much easier and quite sharp. With an A and up you can change the aperture via your controls, so no need to play with the ring at all. I strongly dislike trying to compose stopped down, hated that on my old Nikon too. For the price I would consider an FA 1.7, not ridiculously expensive and lets you have the autofocus.