Luminous Landscape Forum

Equipment & Techniques => Mirrorless Cameras => Topic started by: bluekorn on September 10, 2014, 04:58:38 pm

Title: When does a prme lens make a difference relative to print size?
Post by: bluekorn on September 10, 2014, 04:58:38 pm
The point of this inquiry is not about whether I'm satisfied with the equipment I have. I am making 9x12 color prints with my Fuji XE 2 and 18-55 zoom set at 23mm focal length. What I'm curious about is whether or not I should see any visible difference in image quality, (whatever that means to you) if I shoot the same 9x12 (a relatively small print) with the Fuji 23mm prime set at the same f stop. In other words, all else being equal, f stop, shutter speed, ISO, angle of view, etc., is there some arbitrary point as print size increases that a prime lens shows its superiority in image quality over a zoom at the same focal length or will a prime show improved image quality (again, whatever that means to you) no matter how small the print? Thank you.

Peter
Title: Re: When does a prme lens make a difference relative to print size?
Post by: elf on September 10, 2014, 05:20:45 pm
Look up the MTF for each lens to see if there is a measurable difference. 
Title: Re: When does a prme lens make a difference relative to print size?
Post by: Ken Bennett on September 10, 2014, 05:58:55 pm
I have both lenses. They are both very sharp, and I would not expect to see much if any difference in prints at 9x12, or even at 16x24 with careful technique.

The reason to own the 23 is for the f/1.4 maximum aperture, which the zoom can't touch :) For candid, street, photo-J, and general work I use the 23. For work on a tripod at middling apertures, I prefer the zoom so I can frame exactly what I want.
Title: Re: When does a prme lens make a difference relative to print size?
Post by: Misirlou on September 10, 2014, 06:03:20 pm
Are you familiar with the concept of "bokeh"?
Title: Re: When does a prme lens make a difference relative to print size?
Post by: bluekorn on September 11, 2014, 10:38:47 am
Thank you. I think then I will buy a prime outside of the 18-55 range, probably the 14mm. I very much appreciate the feedback.

Peter
Title: Re: When does a prme lens make a difference relative to print size?
Post by: Paul80 on September 11, 2014, 02:22:42 pm
Are you familiar with the concept of "bokeh"?

"Bokeh" is that the thing that makes Canon Lens owners feel superior to Nikon Lens owners  8)

Runs away putting his coat and tin hat on  ;)
Title: Re: When does a prme lens make a difference relative to print size?
Post by: Misirlou on September 11, 2014, 03:04:54 pm
"Bokeh" is that the thing that makes Canon Lens owners feel superior to Nikon Lens owners  8)

Runs away putting his coat and tin hat on  ;)

Good lord, that's the kind of statement that gets people injured!

The truly faithful regard the Leica R 90 F/2 Summicron as the ultimate example. Or at least that's how I was indoctrinated.
Title: Re: When does a prme lens make a difference relative to print size?
Post by: PeterAit on September 11, 2014, 03:49:40 pm
The point of this inquiry is not about whether I'm satisfied with the equipment I have. I am making 9x12 color prints with my Fuji XE 2 and 18-55 zoom set at 23mm focal length. What I'm curious about is whether or not I should see any visible difference in image quality, (whatever that means to you) if I shoot the same 9x12 (a relatively small print) with the Fuji 23mm prime set at the same f stop. In other words, all else being equal, f stop, shutter speed, ISO, angle of view, etc., is there some arbitrary point as print size increases that a prime lens shows its superiority in image quality over a zoom at the same focal length or will a prime show improved image quality (again, whatever that means to you) no matter how small the print? Thank you.

Peter

There's no general rule regarding primes versus zooms. It used to be the case that zooms were reliably inferior, but lens design and construction have come a long way since then. You just have to compare the specific lenses in question. It's also the case that an aspect of a zoom that's inferior to a prime, such as distortion, can often be fixed in post-processing, so the "inferiority" is real in a technical sense but irrelevant in terms of the final image. Finally, it is always wise to keep in mind that the real quality of your images has more to do with subject, composition, and lighting than it does with sharpness, which gets way more emphasis than it deserves on this forum.
Title: Re: When does a prme lens make a difference relative to print size?
Post by: ErikKaffehr on September 11, 2014, 04:35:00 pm
Hi,

Good points. In my case I usually had somewhat premium zooms and "normal" primes. In general I did not feel that the primes were better, so they have seen little use.

Clearly, there are some truly excellent primes around, like the Otus, Sigma Art and quite a few other lenses. That may change the equation.

Best regards
Erik

There's no general rule regarding primes versus zooms. It used to be the case that zooms were reliably inferior, but lens design and construction have come a long way since then. You just have to compare the specific lenses in question. It's also the case that an aspect of a zoom that's inferior to a prime, such as distortion, can often be fixed in post-processing, so the "inferiority" is real in a technical sense but irrelevant in terms of the final image. Finally, it is always wise to keep in mind that the real quality of your images has more to do with subject, composition, and lighting than it does with sharpness, which gets way more emphasis than it deserves on this forum.
Title: Re: When does a prme lens make a difference relative to print size?
Post by: maddogmurph on September 17, 2014, 03:01:55 pm
I own both of these lenses, and have done exactly what you're asking about.  What I found is that the corners of the prime lens were not as sharp as the corners of my 18-55mm zoom lens with all settings the same.  The center of the prime was not more sharp that I could see but simply equal, and the corners of the frame lost sharpness compared to the zoom. 

However, my prime introduces depth of field which is not possible with my zoom.  See the attached pictures, taken with my prime.  If you want depth of field, the only way to get it is through a prime.
Title: Re: When does a prme lens make a difference relative to print size?
Post by: maddogmurph on September 17, 2014, 03:04:44 pm
Oh, sorry, I'm mistaken, I own the 35mm...
Title: Re: When does a prme lens make a difference relative to print size?
Post by: Petrus on September 17, 2014, 04:23:51 pm
  If you want depth of field, the only way to get it is through a prime.

I suppose you mean "less depth of field"…

I find that using a prime lens changes the shooting style, as I have to frame differently and use "foot zoom" to optimize the framing. Zoom can make the shooter lazy, not good. If I go on a news assignment, I take zooms (14-24, 24-70, 70-200). If I go on a portrait or "art" assignments, I take fast 35, 50, 85 and 135 primes.
Title: Re: When does a prme lens make a difference relative to print size?
Post by: elf on September 17, 2014, 06:28:39 pm

However, my prime introduces depth of field which is not possible with my zoom.  See the attached pictures, taken with my prime.  If you want depth of field, the only way to get it is through a prime.


Depth of field is entirely dependent on focal length and aperture.  Whether the lens is prime or zoom is irrelevant.
Title: Re: When does a prme lens make a difference relative to print size?
Post by: Tony Jay on September 17, 2014, 06:49:34 pm
Depth of field is entirely dependent on focal length and aperture.  Whether the lens is prime or zoom is irrelevant.
Where one chooses to focus also plays a role.
Close focusing reduces depth of field and focusing on a distant object broadens the depth of field.
However, it is absolutely correct that whatever the depth of field is can be exactly predicted if one knows the focal length of the lens (or, in the case of a zoom what focal length is being used), aperture, and focusing distance.

Whether one uses a zoom or a prime lens is completely inconsequential.

Tony Jay
Title: Re: When does a prme lens make a difference relative to print size?
Post by: ErikKaffehr on September 18, 2014, 12:30:19 am
Hi,


The problem with foot zoom is that it changes perspective. Also choice of vantage point is often limited, like finding a high position, getting around vegetation etc. Sometimes just a 15 cm change of position can make a a lot of difference.

Best regard
Erik


I suppose you mean "less depth of field"…

I find that using a prime lens changes the shooting style, as I have to frame differently and use "foot zoom" to optimize the framing. Zoom can make the shooter lazy, not good. If I go on a news assignment, I take zooms (14-24, 24-70, 70-200). If I go on a portrait or "art" assignments, I take fast 35, 50, 85 and 135 primes.
Title: Re: When does a prme lens make a difference relative to print size?
Post by: Petrus on September 18, 2014, 01:50:29 am
Hi,

The problem with foot zoom is that it changes perspective. Also choice of vantage point is often limited, like finding a high position, getting around vegetation etc. Sometimes just a 15 cm change of position can make a a lot of difference.

Best regard
Erik

That is the reason I use zooms when shooting events/news and primes for "artsy" stuff, where there is time to move around, change backgrounds and play with shallow DOF (primes f1.4 or f2, zooms f2.8…)
Title: Re: When does a prme lens make a difference relative to print size?
Post by: bluekorn on September 18, 2014, 10:36:29 am
I seem to experience that vantage point problem frequently when climbing about for the best angle and gaining height is where it most frequently occurs. Without really knowing it I've been fortunate to be using a zoom as there's been no place left to go. I mostly shoot landscapes where a greater depth of field seems best but the examples shown with the 35 do illustrate the wonderful illusion of depth in an image with a fast wide open aperture. Lots of good information. Thank you all again.