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09-18-2010, 07:46 PM   #1
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50mm vs. 55mm

This is a very similar topic I opened about a month ago, but I would like some further input.

I am trying to justify owning both a 50mm and 55mm lens. I tend to sell anything I do not need.

I have a 50mm and 55mm prime... both of similar quality as far as image quality goes. Of course, they are different, but rather similar in many regards.

I notice some differences between the 55mm and 50mm OOF areas. Circles of confusion tend to be MUCH larger with the 55mm lens. I somewhat prefer the OOF areas of the 55mm.

However, in real shooting situations I doubt these differences will really matter, and more importantly, the 50mm is an A series, which is much easier to shoot with in dynamic light.

So, from the pros, I would like to know if you find a real use for both a 50 and 55 mm lens in your set up, or if you tend to use only one of them? Does it make sense for me to keep both?

09-18-2010, 08:52 PM   #2
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Myself i own only 3 - 50s, a K55/1.8, 50FA/1.4 and a SMC Tak 55 film they are each attached to AF film body (MZ5n), digital body and MF body (spomatic) sometimes the K lens sleeps with the digital body so in my case, yes and no one is getting kicked outta bed. I somewhat prefer my K55 as in my eyes the bokeh is much better also i think i like the colours/resolution/contrast/tones etc a little more too
09-18-2010, 09:06 PM   #3
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1.4/50 and 1.8/55? Imho, your observation about coc differences is spot on. I find use for both -- for me the 1.4/50 is better for portraits, for really throwing the background out of focus to make the subject more sharply prominent, and when f/1.4 is needed, while the 1.8/55 is better for landscapes and less defined subjects where bokeh is still important. Those factors have become even more evident since I upgraded to a full-frame body.
09-19-2010, 01:57 AM   #4
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QuoteOriginally posted by rhodopsin Quote
Those factors have become even more evident since I upgraded to a full-frame body.
You upgraded to what??? please explain

09-19-2010, 07:34 AM   #5
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QuoteOriginally posted by danielausparis Quote
You upgraded to what??? please explain
Check my profile for equipment list...
09-19-2010, 08:51 AM   #6
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I have an A50 1.7, FA50 1.4, and a K55 1.8. When I take a 50 (and that's becoming less frequent), it's going to be the FA50 or A501.7. The reasons are primarily the metering convenience offered by the A and FA lens, and of course, the autofocus (FA).

The other reason is the colors/contrast of the A50 and FA50 lenses. There's something how about how the shadow, and highlights are rendered along with the colours from those lenses that the K55, or many other lenses for that matter, cannot match, imho.
09-19-2010, 09:04 AM   #7
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QuoteOriginally posted by paperbag846 Quote
Circles of confusion tend to be MUCH larger with the 55mm lens.
Do you know what Circle of Confusion means?
09-19-2010, 10:14 AM   #8
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QuoteOriginally posted by alohadave Quote
Do you know what Circle of Confusion means?
Maybe I did not use the term completely correctly.

I understand COC to be the point at which an "in focus" point and an "out of focus" point overlap.

With the 55mm, I find the same "confused circles" i.e., out of focus points, to be larger than with the 50mm.

09-19-2010, 10:19 AM   #9
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I tried to avoid bias here,

The lenses are the A 50mm 1.7, and the K 55mm 1.8.

Do I find a use for both? Yes... but I feel it is mostly fabricated. OOF areas on the 1.8 are a little smoother. It is also harder to get the light right with stop down metering.

So I'm trying to break it down by focal legnth. My feeling is that owning a 50 and a 75-85 lens would be better for portraits, than a 55 and 50 lens.

But I don't know! I have a buyer willing to give me 80 for the K55, which I feel is a good deal for me... but part of me feels like letting go of a K mount K55 would be stupid because they are hard to find, and it's only 80 bucks...
09-19-2010, 11:18 AM   #10
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QuoteOriginally posted by paperbag846 Quote
I tried to avoid bias here,

The lenses are the A 50mm 1.7, and the K 55mm 1.8.

Do I find a use for both? Yes... but I feel it is mostly fabricated. OOF areas on the 1.8 are a little smoother. It is also harder to get the light right with stop down metering.

So I'm trying to break it down by focal legnth. My feeling is that owning a 50 and a 75-85 lens would be better for portraits, than a 55 and 50 lens.

But I don't know! I have a buyer willing to give me 80 for the K55, which I feel is a good deal for me... but part of me feels like letting go of a K mount K55 would be stupid because they are hard to find, and it's only 80 bucks...
I also own both of these lenses and except for convenience and its compact size, I would let the A 50/1.7 go. The K 55/1.8 is better in every other way.


Steve

(Of course, I would never let it go...I love my 50s...every last one of them!)
09-19-2010, 11:27 AM   #11
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QuoteOriginally posted by paperbag846 Quote
Maybe I did not use the term completely correctly.

I understand COC to be the point at which an "in focus" point and an "out of focus" point overlap.

With the 55mm, I find the same "confused circles" i.e., out of focus points, to be larger than with the 50mm.
CoC has nothing to do with what you are talking about.

It's the smallest circle formed by a point that is indistinguishable from a point. Lenes do not render points as points, but rather as circles. When the circle of confusion is small enough, you will see the circle as a point.

Circle of confusion - Wikipedia, the free encyclopedia
09-19-2010, 11:48 AM   #12
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QuoteOriginally posted by alohadave Quote
CoC has nothing to do with what you are talking about.

It's the smallest circle formed by a point that is indistinguishable from a point. Lenes do not render points as points, but rather as circles. When the circle of confusion is small enough, you will see the circle as a point.

Circle of confusion - Wikipedia, the free encyclopedia
Thanks for the correction, but at the same time, this really has nothing to do with my question... I'm just asking if you people find a use for both 55mm and 50mm.

I have limited funds, but I'm just looking for a good portrait lens. I feel like the 55mm is good for that... but if there is an inexpensive option at a longer length (75 - 85mm) than I would like to know about it.
09-19-2010, 12:07 PM   #13
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QuoteOriginally posted by paperbag846 Quote
Thanks for the correction, but at the same time, this really has nothing to do with my question... I'm just asking if you people find a use for both 55mm and 50mm.

I have limited funds, but I'm just looking for a good portrait lens. I feel like the 55mm is good for that... but if there is an inexpensive option at a longer length (75 - 85mm) than I would like to know about it.
Not only do tons of people own multiple 50-ish lenses for good reasons (they each have their own characteristics), but 75 to 85 lenses are a totally different category.

I guess my question is, what is your question? And what answer are you looking for?

We all have limited funds here, yet many of us realize that we have to have lenses that cover both 50-ish and 75 to 85-ish.

They're two different animals.
09-19-2010, 12:42 PM   #14
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I'm fairly new to the looks of lenses, so that I'm sure is not helping .

The "look" of my 50mm and 55mm are both VERY similar and somewhat different. What I don't know is how much of that difference is in the focal length.

My thought is that if the bokeh of the 55mm is so much softer than the 50mm, then a true portrait lens (the 77mm, or realistically, an old 85mm) would be even nicer. I love the shallow DOF, creamy background look.

Maybe I really need to replace the A 50 1.7 with a 50mm 1.4, and keep the 55mm (because there is no way I can afford the DAstar 55mm 1.4).

I suppose I am asking... do you people have a use for both the 55 and 50 lengths? Your answer is "yes" and I appreciate that.
09-19-2010, 01:20 PM   #15
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QuoteOriginally posted by paperbag846 Quote
My thought is that if the bokeh of the 55mm is so much softer than the 50mm, then a true portrait lens (the 77mm, or realistically, an old 85mm) would be even nicer. I love the shallow DOF, creamy background look.
That's not an assumption that you can reliably make. Bokeh is dependent on several factors, and it is a secondary design priority for most lens designs.
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