50 mm: 1.4 or 1.7?

[anktonio]

Many people prefer a 1.4. The reason is a half step. But is this the only reason? So marked is the difference in bokeh? Is it better ISO up a little to match the values​​? Is it reasonable weight and price difference? The picture quality is different? Do you often be better than 1.7? A lens is a great compromise solutions. Does greater aperture means less contrast and aberrations?... One of the reasons for our choice can be emotional, but we chose well?

Regards.

[drjs]

[Basilisk]

f1.4 to f1.8 (which is a more common option than f1.7) is closer to whole stop than a third of a stop - so a real difference in low light situations (actual light transmission might be a bit less than that of course)

Also f1.4 has nearly 30% more background blur wide open - which I would say is noticeable.

It is worth getting a handle on when this might be useful. For head and shoulders portraits, DOF at f1.4 is razor thin, and you probably shut down a bit - if only to get both eyes in focus. Full-length portraits, where you want to get nice separation from the background, f1.4 suddenly seems more useful (other work arounds, like moving your subject away from the background, or using a longer lens are also an option)

[drjs]

[simbon4o]

For me 1.7 is safer choice. Most of them are sharper and less prone to flare. Most of the mare usable wide open... Most of them has less CAs.
Problems of the 1.7(and 1. are the aperture blades. Most of them are with 6 straight ones which creates awful bokeh closed down. There are only few with more curved blades or with more than 6.

About 1.4 - most of them are very awful at 1.4, almost unusable. More CAs, more prone to flare, ... most of them are usable from 2.0.
Good thing about most 1.4s is that they are good at 2.0 - smooth bokeh, many of them are with more than 6 aperture blades.

So overall - it is easier to find good 50 1.7 than 50 1.4 and they are cheaper. Some of them are even better than most 50 1.4 and not that slow actually.

Just for example - my Zenitar 50 1.7 is more like 1.5 or even 1.4 because it gives me speed like my 50 1.4 Pentax and the Zenitar is sharper at every aperture with smoother bokeh and it is cheaper. The contrast is worse but that's Russian coatings fault .

[tikkathree]

I think, dodging flames, brickbats and rotten tomatoes, that people have a tendency to buy 50mm primes subjectively rather than objectively.

So EOS nifty fifty? That'd better be the 1.8 MkI then, not the later plastic "junk lens".

1.8? Really? Oh dear, that didn't cost much so the 1.4 is the one to have.

Yeah but the 1.2... so much more poke, looks like it costsalot and it does costalot so that's the one to be seen with.

Performance? Whaddya mean performance? Widest is best innit?

I'm here to tell you that I chopped in a perfectly good but noisy 1.8 Mk1 for a 1.4 and wish I hadn't bothered. What I do shoot with most of the time on the 5DII is the FD 55mm 1.2 which trifox converted for me.

[Nordentro]

A 50mm 1.4 is quite nice as a portrait lens on a crop camera. It's softer and bokeh is in general better with less dept of field. It is also nice when shooting flowers... 50mm 1.7 is a better walk around lens with mixed use IMO

[Lloydy]

[poilu]

1.7 are budget lenses, almost as good as the 1.4 version
this is what Zeiss wrote about the contax 50:1.7

[fermy]

I'm firmly in f1.4 camp. Usually f1.4 is a better corrected lens. For example all Minolta MC/MD 50/1.4 lenses feature 7 elements, while all slower alternatives have only 6. Same story for Konica and Canon FD. On top of that FD 50/1.4 used special glasses, which 50/1.8 did not.

Typically f1.4 v f1.8 gives you:
- extra 2/3 stops of light for low light or DOF control
- Better IQ at large apertures. For example an f1.4 lens stopped to f1.8 is typically sharper and contrastier than f1.8 lens WO.
- Sometimes better build quality, less plastic, more metal.
- Sometimes more blades for better looking OOF highlights. For example, FD 50/1.4 has 8 blades v 6 blades for 1.8
- Sometimes better coating. Again FD 50/1.4 used SSC, while 50/1.8 used SC. Possibly true with other lens manufacturers as well. Konica and Minolta coatings do give different colors on my 50/1.4 and 50/1.7 versions.

You pay for that with higher weight and higher price and then the question is whether the improvements you get are worth those penalties. And since many great f1.4 lenses are still under $100, IMHO they are clear winners v f1.8 versions. Now if we get into Zeiss and Leica territory, the balance does change. If one looks say at Leica Summicron-R v Summilux-R, that's 300 Euros v 1000 for 1 stop. Summilux is a clear loser in my eyes.

[tikkathree]

[Lloydy]

[fermy]

[Attila]

Really no matter, my safe zone start from f4

[Excalibur]

[anktonio]

Thank you very much everyone for your responses, which have been much better than my question. There are some differences in the conclusions, but this makes me think that all you're right, and that there are many different reasons to decide between one or the other.

drjs ..."In almost all cases, the 0.8 stop of light may not be the most compelling reason to pick one vs. the other when high ISO performance is so good on modern DSLR"... 0.8 or less... Your logic is crushing! I agree.

Basilisk ..."f1.4 to f1.8 (which is a more common option than f1.7) is closer to whole stop than a third of a stop - so a real difference in low light situations (actual light transmission might be a bit less than that of course)"... Good remarks.

..."Also f1.4 has nearly 30% more background blur wide open - which I would say is noticeable"... The blur difference is not much (in my opinion), but it is certainly noticeable... with the cost of degradation of the subject, which can be secondary or not.

simbon4o ..."About 1.4 - most of them are very awful at 1.4, almost unusable. More CAs, more prone to flare"... Your experience is identical to mine.

tikkathree ...""...

Nordentro ..."It's softer and bokeh is in general better with less dept of field"... Indeed. That softness are optical imperfections, physical limits, they almost never help me, except in very rare occasions. But I know that this is a must for many people.

poilu ..."1.7 are budget lenses, almost as good as the 1.4 version"... I agree on this and I almost dare to say that they are indistinguishable in practice.

Attila ..."Really no matter, my safe zone start from f4"... oh, I believed that for you f4 is nonexistent

fermy ..."the question is whether the improvements you get are worth those penalties"... Indeed.

..." an f1.4 lens stopped to f1.8 is typically sharper and contrastier than f1.8 lens"...

I did some tests obviously unscientific, although these tests do indoors, the light was slightly changed, I had to make up a little to get similar results. I think enough for a good eye. They are direct JPG. I preferred a FF for this test, but I only have a G1. Imagine that the test you did with FF and then cut a quarter to 100% crop Lens: FD 50/1.4, Planar 50/1.8 and Yashinon DS-M 50/1.7, all multicoated.

Canon FD 50/1.4 stopped at f71.7-1.8:

Full resolution: http://farm9.staticflickr.com/8544/8683217846_55d932b203_o.jpg

Yashinon DS-M 50/1.7 at f/1.7:

Full resolution: http://farm9.staticflickr.com/8546/8683220514_755d20d1de_o.jpg

Carl Zeiss Planar 50/1.8 at f/1.8:

Full resolution: http://farm9.staticflickr.com/8546/8683223202_cb26f927ed_o.jpg

Regards.

[Rawit]

Your last image url has a typo, the correct one is:

http://farm9.staticflickr.com/8546/8683223202_cb26f927ed_o.jpg

It seems the Canon sample is focussed on the edge of the cutting board, where the other two are focussed on the orange?

[anktonio]

Thank you. Fixed. It is assumed that all are focused at sticker text on the orange... maybe I should repeat the test :/

[Oldhand]

[Basilisk]

[drjs]

Thanks for the round up. Wonderful discussion.

I recommend getting them all, you can never have too many lenses!

[Rawit]

The differences are indeed subtle. It makes me even more curious how expensive lenses like the Leica's or M-Hexanon's compare to this.

[simbon4o]

here some samples from my 50s
here some samples 50 1.7 vs 50 1.4
here some samples more 50s on 16mp matrix

Pentax M 50 1.4@1.4

Zenitar 50 1.7@1.7


And crops
1.4

1.7


And crops at 2.0

Pentax

Zenitar


So for me the 1.7 lenses are much safer and cheaper choice. I have recently bought A 50 1.2 pentax and when compared it to my other lenses it was softer closed down, yes the smoothness of the bokeh is great at 1.8 and further, but still Zenitar is sharper. More lens elements are for correcting the problems of bigger lenses. More lens elements and bigger ones causes only problems for sharpness. Actually with distance from the object on focus the difference between 1.2 and 1.7 is getting closer to nothing in terms of defocus and since most of 50 1.4 lenses needs closing down to 2.0 ... I have made a comparison test of Pentax A 50 1.2, FA 50 1.4 and Zenitar 50 1.7 in terms of bokeh and I will post it soon

[fermy]

Doh, of course a shot @f1.4 will look softer than the one @f1.7 even due to different DOF, not to mention that the makers are completely different. I guess APO-Summicron ASPH for $7K will be sharper than all lenses here, so are we to conclude that f2.0 lenses are the safest bet

Canon FD 50mm f1.4 SSC

Canon FD 50mm f1.8


Both tests on NEX-3 performed by the same guy: http://erphotoreview.com/wordpress/

[simbon4o]

About 2.0 lenses - no most of them are budget to the limit lenses and are much worse performing than 1.4 and 1.7/1.8 models.
Summicron 50 1.4 is maybe the only 50 1.4 that I think is perfectly usable at 1.4 and there is a price for it ....
Another expensive lens - Planar 50 1.4... not so usable at 1.4 so it depends.