[sarcasticcrab]

Does anyone know the difference between these two lenses? I would like to keep the ‘best’ and sell the other.

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[photoptimist]

The left one is the M version: SMC Pentax-M 50mm F1.4 Reviews - M Prime Lenses - Pentax Lens Reviews & Lens Database

The right one is the K version: SMC Pentax 50mm F1.4 Reviews - K Prime Lenses - Pentax Lens Reviews & Lens Database

[boriscleto]

The one on the left has a 49mm filter thread, the one on the right has a 52mm filter thread.

[BigMackCam]

The one on the left has a 49mm filter thread, the one on the right has a 52mm filter thread.

And that's the only difference? I know the formula is the same, but is it the same glass, same coatings, same build quality, same ... ... etc.?

[boriscleto]

And that's the only difference? Same glass, same coatings, same build quality, same ... ... etc.?

Functionally there is no difference. Both have 7 elements in 6 groups, 8 aperture blades, and SMC coatings. The one on the left weighs 235 grams and the one on the right weighs 265 grams.

[TwoUptons]

My understanding is that they are so similar optically that any decision would need to be made based on sample variation and personal preference.

I’d suggest a test

But if they were the same, I would keep the M because I have more 49mm filters...

Other people like the ergonomics of the older “K” bodies...

Either way, you win...

-Eric

[gofour3]

The K50/1.4 is physically bigger, so you may find it to be a better handling lens than the smaller M50/1.4.

I prefer the bigger K Series lens, however you might not. As the optics/build are similar, that would be the deciding factor for me.

Phil.

[ismaelg]

Use this scientific approach:
Take a coin
Assign Heads to one lens and tail to the other
Flip the coin in the air 3 times and record heads or tail
Keep the one that wins at least 2 out of 3



I personally love the M series but it will be down to each sample. If they perform equally (as expected) you can see how the prices are going and sell the one that may sell at a higher price.

Thanks,

[swanlefitte]

With older glass copy variations can easily trump anything else. You really need to try them.

[boriscleto]

I guess I don't understand all this talk of "selling"...

Like Pokemon, Gotta Catch 'em All...

[Not a Number]

And the scientific method fails. You need to get in touch with your unconscious feelings. Flip the coin and think on how you feel about the result? Disappointed? Happy? Indifferent? Once you do that you'll know what the choice is.

I'm with Boris. Collect 'em all

[dbs]

Hi Sarcasticcrab

I don't have either of these..

First use both blind judge the resulting photos, if unsure do it 3 more times.
After that grab a stranger off the street and ask their opinion of the said photos
Its going to take awhile
The said stranger can also flip the coins so no bias is entered into....also best of 3.





what you sell lenses ...who'd thunk that

At your service.

Dave

[Lowell Goudge]

Note, SMC was not a single unified formula, it evolved over time, the M coatings should be better, but I like the k series lenses generally because they “feel” better, My experience is the focus throw is much smoother and more consistent, the Mseries feel cheap (sorry I know this doesn’t help much)

[clackers]

It's Sophie's Choice!

[monochrome]

Note, SMC was not a single unified formula, it evolved over time, the M coatings should be better, but I like the k series lenses generally because they “feel” better, My experience is the focus throw is much smoother and more consistent, the Mseries feel cheap (sorry I know this doesn’t help much)

IMO - having both lenses (and many other 50mm Pentax lenses from the early 50’s to the most recent) - characterizing one SMC coating formula as better or worse than another doesn’t tell the whole story. They render differently.

In my experience the changes to the M era and particularly A era SMC coating formula made the lenses noticeably cooler than the K and earlier SMC formula variants. My K50/1.4 is noticeably warmer than my M and A 50/1.4s. The K version shades more toward a hint of sepia while the later variants lean toward a bluish cast (that tendency toward a progressively cooler cast reaches its zenith with the HD coating). I have noticed the same tendency comparing other similar focal lengths - K105/2.8 versus M100/2.8 and K150/4 vs. M150/3.5 in particular.

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