Fast lenses....do you sacrifice speed for sharpness

lesmore49 · 08-08-2014, 01:05 PM

I have some fast lenses...F 1.4, F 1.8, etc. I rarely shoot them at F 1.4, 1.8 due to sharpness.

I think it's great to have an F 1.8....but if the sharpness ain't there (in my view) till about F 3.5....maybe F 2.8....I've never been able to see the value, especially for advanced amateur photography.

I understand the bokeh thing.

I wonder if...really fast lenses....say F 1.4 to F 1.8 at these F stops....are worth it, particularly in these days of ever increasing ISO....with ever decreasing noise....or grain as we used to call it.

What's your view ?

JinDesu · 08-08-2014, 01:07 PM

It could be sharp enough. For example, both my Sigma 50 F1.4 and DA*55 F1.4 are sharp enough for portraits and general photography wide open. Stopping down to F2 makes them sharper, but sometimes I don't really need that additional sharpness when I can get away with twice the shutter speed.

**luftfluss** · 08-08-2014, 01:08 PM

Originally posted by lesmore49

I have some fast lenses...F 1.4, F 1.8, etc. I rarely shoot them at F 1.4, 1.8 due to sharpness.

I think it's great to have an F 1.8....but if the sharpness ain't there (in my view) till about F 3.5....maybe F 2.8....I've never been able to see the value, especially for advanced amateur photography.

I understand the bokeh thing.

I wonder if...really fast lenses....say F 1.4 to F 1.8 at these F stops....are worth it, particularly in these days of ever increasing ISO....with ever decreasing noise....or grain as we used to call it.

What's your view ?

Are you sure that the resultant images are soft due to lack of lens sharpness, or because of low contrast and/or such a small area is in focus when the lens is wide open? (I've struggled with this a bunch over the years)

Sometimes, all you need is for one (small) portion of the image to be sharper than the rest of the image.

Adam · 08-08-2014, 01:09 PM

Originally posted by lesmore49

I wonder if...really fast lenses....say F 1.4 to F 1.8 at these F stops....are worth it, particularly in these days of ever increasing ISO....with ever decreasing noise....or grain as we used to call it.

I think they are, but for specific applications. For example, when doing astrophotography, it's nice to have a F1.4 lens since you don't want to have to bump the ISO too high. Quality fast lenses should be very sharp when stopped down by around 1 stop. If a lens isn't acceptably sharp until F3.5 I would agree that it's not worth it.

Adam
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Paul the Sunman · 08-08-2014, 01:20 PM - **1 Like**

Another advantage of a fast lens is the brighter image in the viewfinder. This can be useful, especially if focusing manually (where additionally the reduced DOF makes focusing more precise).

cali92rs · 08-08-2014, 01:44 PM

If you are shooting at F1.4 vs F2.8, that is the difference between a 1sec exposure and a 1/4 exposure.
I think most folks can shoot 1/4 sec handheld with acceptable results, with a 50mm lens (assuming good "trigger discipline").
A 1sec shutter will be nearly impossible to get decent results handheld.

I remember when i had my 35mm f2.8 macro. I was amazed how many times i thought i was in OK light indoors, yet I still needed to use 3200 or 6400 ISO to keep my shutter speed reasonably fast. 3200 and 6400 are OK in a pinch, but i wouldnt want to use them for anything critical...especially with APS-C sensors.

Plus, noise is different than grain. Chroma noise, when you clean it up will make your images look very plasticy.
In the film days, you did have grain with more sensitive films, but the detail wasn't stripped like it is with noise reduction software.

lesmore49 · 08-08-2014, 02:18 PM

Originally posted by cali92rs

If you are shooting at F1.4 vs F2.8, that is the difference between a 1sec exposure and a 1/4 exposure.
I think most folks can shoot 1/4 sec handheld with acceptable results, with a 50mm lens (assuming good "trigger discipline").
A 1sec shutter will be nearly impossible to get decent results handheld.

I remember when i had my 35mm f2.8 macro. I was amazed how many times i thought i was in OK light indoors, yet I still needed to use 3200 or 6400 ISO to keep my shutter speed reasonably fast. 3200 and 6400 are OK in a pinch, but i wouldnt want to use them for anything critical...especially with APS-C sensors.

Plus, noise is different than grain. Chroma noise, when you clean it up will make your images look very plasticy.
In the film days, you did have grain with more sensitive films, but the detail wasn't stripped like it is with noise reduction software.

I do not care for noise or grain. Back in the film days....I recall pushing B+W Tri X (think it was 400 asa, but I could be wrong) to 600 asa. Looked grainy and to my eyes....detail was poor... and I was not happy with the result. Back then ('60's) there was an element in photography that used to sing the praises of 'grain'. I was not part of that choir.

Unregistered User · 08-08-2014, 02:19 PM

Originally posted by lesmore49

I have some fast lenses...F 1.4, F 1.8, etc. I rarely shoot them at F 1.4, 1.8 due to sharpness.

I think it's great to have an F 1.8....but if the sharpness ain't there (in my view) till about F 3.5....maybe F 2.8....I've never been able to see the value, especially for advanced amateur photography.

I understand the bokeh thing.

I wonder if...really fast lenses....say F 1.4 to F 1.8 at these F stops....are worth it, particularly in these days of ever increasing ISO....with ever decreasing noise....or grain as we used to call it.

What's your view ?

I have a book with hundreds upon hundreds of photos taken by the late John Hedgecoe, a professional Pentax shooter. Among these hundreds of photos I could find only one (!) shot at f/2 or larger aperture - f/2 in his case.

I had a 50mm f/1.4 lens, but I eventually gave it away. The fastest lens I have now is the Helios 58mm f/2, and I don't need anything faster.

**Kerrowdown** · 08-08-2014, 02:22 PM

As a manual lens man, a bright viewfinder is everything for me especially when used with a Katzeye screens.

SpecialK · 08-08-2014, 02:24 PM

The rule of thumb is that the sharpest aperture is about 2 stops from wide open. So, the bigger the maximum aperture, the bigger will be the "optimum" aperture.

A recent graph in one of the threads indicates f5.6, not f8, was the optimum, regardless of the f1.4 or f2.8 max aperture...

ElJamoquio · 08-08-2014, 02:27 PM

Originally posted by lesmore49

I have some fast lenses...F 1.4, F 1.8, etc. I rarely shoot them at F 1.4, 1.8 due to sharpness.

I think it's great to have an F 1.8....but if the sharpness ain't there (in my view) till about F 3.5....maybe F 2.8....I've never been able to see the value, especially for advanced amateur photography.

I understand the bokeh thing.

I wonder if...really fast lenses....say F 1.4 to F 1.8 at these F stops....are worth it, particularly in these days of ever increasing ISO....with ever decreasing noise....or grain as we used to call it.

What's your view ?

I like having F/1.8 available. F/1.4 or faster is rarely used. I'm debating purchasing vs renting a fast lens for use in ultra-low-light.

Paul the Sunman · 08-08-2014, 02:55 PM - **2 Likes**

I do not criticize oil paintings because I can see the brush strokes. I do not criticize high iso film photos because I can see the grain. These are in the nature of the medium. It is the skill of the artist that uses the character of the medium to create an impression, a mood ... in short, art.

**jrpower10** · 08-08-2014, 03:29 PM

Seen this before and never seen anyone point out that, the faster the lens, the faster the optimal aperture probably is. If in general a lens hits peak sharpness about 2 stops from wide open, a 1.4 lens will be sharpest at 2.8, whereas a 2.8 lens will be sharpest at 5.6, etc. So, even though a fast lens is sharpest stopped down, so is virtually every other lens. My 31 limited is sharper at f4 than at f1.8, but that doesn't make it a bad lens, even wide open. It's sharper wide open than my 16-50 f2.8 wide open (OK apples and oranges, but you get the point). Some fast lenses probably aren't worth it because they just aren't that good, but a good fast lens is, IMHO.

carrrlangas · 08-08-2014, 03:53 PM

I don`t think any of the modern lenses is bad wide open. I think nailing focus and having enough depth of field are more relevant than how sharp the lens is wide open. I use the largest aperture keeping AF / DoF ok, as I find dynamic range suffers quite a bit from higher ISOs. I suspect there`s a problem with my PP workflow and/or my expectations.

Unregistered User · 08-08-2014, 04:00 PM

Originally posted by Paul the Sunman

I do not criticize oil paintings because I can see the brush strokes. I do not criticize high iso film photos because I can see the grain. These are in the nature of the medium. It is the skill of the artist that uses the character of the medium to create an impression, a mood ... in short, art.

Some risible claptrap right there. The guy had a practical question; what he gets instead is pseudoprofound malarkey.

08-08-2014, 01:05 PM	#1
lesmore49 Pentaxian Join Date: Nov 2007 Location: Western Canada Posts: 12,325	Fast lenses....do you sacrifice speed for sharpness I have some fast lenses...F 1.4, F 1.8, etc. I rarely shoot them at F 1.4, 1.8 due to sharpness. I think it's great to have an F 1.8....but if the sharpness ain't there (in my view) till about F 3.5....maybe F 2.8....I've never been able to see the value, especially for advanced amateur photography. I understand the bokeh thing. I wonder if...really fast lenses....say F 1.4 to F 1.8 at these F stops....are worth it, particularly in these days of ever increasing ISO....with ever decreasing noise....or grain as we used to call it. What's your view ?

08-08-2014, 01:20 PM - 1 Like	#5
Paul the Sunman Pentaxian Join Date: Aug 2011 Location: Melbourne Photos: Gallery Posts: 4,842	Another advantage of a fast lens is the brighter image in the viewfinder. This can be useful, especially if focusing manually (where additionally the reduced DOF makes focusing more precise). Last edited by Paul the Sunman; 02-14-2015 at 01:36 PM.

08-08-2014, 02:22 PM	#9
Kerrowdown PEG Moderator Join Date: Aug 2008 Location: Highlands of Scotland... "Hold Infinity in the palm of your hand" - William Blake Photos: Gallery Posts: 57,804	As a manual lens man, a bright viewfinder is everything for me especially when used with a Katzeye screens. Last edited by Kerrowdown; 08-08-2014 at 02:55 PM.

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08-08-2014, 01:07 PM	#2
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	It could be sharp enough. For example, both my Sigma 50 F1.4 and DA*55 F1.4 are sharp enough for portraits and general photography wide open. Stopping down to F2 makes them sharper, but sometimes I don't really need that additional sharpness when I can get away with twice the shutter speed.

08-08-2014, 01:08 PM	#3
luftfluss Site Supporter Join Date: Jun 2011 Location: NJ Photos: Gallery \| Albums Posts: 11,618	Originally posted by lesmore49 I have some fast lenses...F 1.4, F 1.8, etc. I rarely shoot them at F 1.4, 1.8 due to sharpness. I think it's great to have an F 1.8....but if the sharpness ain't there (in my view) till about F 3.5....maybe F 2.8....I've never been able to see the value, especially for advanced amateur photography. I understand the bokeh thing. I wonder if...really fast lenses....say F 1.4 to F 1.8 at these F stops....are worth it, particularly in these days of ever increasing ISO....with ever decreasing noise....or grain as we used to call it. What's your view ? Are you sure that the resultant images are soft due to lack of lens sharpness, or because of low contrast and/or such a small area is in focus when the lens is wide open? (I've struggled with this a bunch over the years) Sometimes, all you need is for one (small) portion of the image to be sharper than the rest of the image.

08-08-2014, 01:09 PM	#4
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,593	Originally posted by lesmore49 I wonder if...really fast lenses....say F 1.4 to F 1.8 at these F stops....are worth it, particularly in these days of ever increasing ISO....with ever decreasing noise....or grain as we used to call it. I think they are, but for specific applications. For example, when doing astrophotography, it's nice to have a F1.4 lens since you don't want to have to bump the ISO too high. Quality fast lenses should be very sharp when stopped down by around 1 stop. If a lens isn't acceptably sharp until F3.5 I would agree that it's not worth it. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

08-08-2014, 01:44 PM	#6
cali92rs Veteran Member Join Date: May 2011 Location: Long Beach, CA Posts: 3,354	If you are shooting at F1.4 vs F2.8, that is the difference between a 1sec exposure and a 1/4 exposure. I think most folks can shoot 1/4 sec handheld with acceptable results, with a 50mm lens (assuming good "trigger discipline"). A 1sec shutter will be nearly impossible to get decent results handheld. I remember when i had my 35mm f2.8 macro. I was amazed how many times i thought i was in OK light indoors, yet I still needed to use 3200 or 6400 ISO to keep my shutter speed reasonably fast. 3200 and 6400 are OK in a pinch, but i wouldnt want to use them for anything critical...especially with APS-C sensors. Plus, noise is different than grain. Chroma noise, when you clean it up will make your images look very plasticy. In the film days, you did have grain with more sensitive films, but the detail wasn't stripped like it is with noise reduction software.

08-08-2014, 02:18 PM	#7
lesmore49 Pentaxian Join Date: Nov 2007 Location: Western Canada Posts: 12,325 Original Poster	Originally posted by cali92rs If you are shooting at F1.4 vs F2.8, that is the difference between a 1sec exposure and a 1/4 exposure. I think most folks can shoot 1/4 sec handheld with acceptable results, with a 50mm lens (assuming good "trigger discipline"). A 1sec shutter will be nearly impossible to get decent results handheld. I remember when i had my 35mm f2.8 macro. I was amazed how many times i thought i was in OK light indoors, yet I still needed to use 3200 or 6400 ISO to keep my shutter speed reasonably fast. 3200 and 6400 are OK in a pinch, but i wouldnt want to use them for anything critical...especially with APS-C sensors. Plus, noise is different than grain. Chroma noise, when you clean it up will make your images look very plasticy. In the film days, you did have grain with more sensitive films, but the detail wasn't stripped like it is with noise reduction software. I do not care for noise or grain. Back in the film days....I recall pushing B+W Tri X (think it was 400 asa, but I could be wrong) to 600 asa. Looked grainy and to my eyes....detail was poor... and I was not happy with the result. Back then ('60's) there was an element in photography that used to sing the praises of 'grain'. I was not part of that choir.

08-08-2014, 02:19 PM	#8
Unregistered User Guest	Originally posted by lesmore49 I have some fast lenses...F 1.4, F 1.8, etc. I rarely shoot them at F 1.4, 1.8 due to sharpness. I think it's great to have an F 1.8....but if the sharpness ain't there (in my view) till about F 3.5....maybe F 2.8....I've never been able to see the value, especially for advanced amateur photography. I understand the bokeh thing. I wonder if...really fast lenses....say F 1.4 to F 1.8 at these F stops....are worth it, particularly in these days of ever increasing ISO....with ever decreasing noise....or grain as we used to call it. What's your view ? I have a book with hundreds upon hundreds of photos taken by the late John Hedgecoe, a professional Pentax shooter. Among these hundreds of photos I could find only one (!) shot at f/2 or larger aperture - f/2 in his case. I had a 50mm f/1.4 lens, but I eventually gave it away. The fastest lens I have now is the Helios 58mm f/2, and I don't need anything faster.

08-08-2014, 02:24 PM	#10
SpecialK Pentaxian Join Date: Dec 2006 Location: So California Photos: Gallery Posts: 16,480	The rule of thumb is that the sharpest aperture is about 2 stops from wide open. So, the bigger the maximum aperture, the bigger will be the "optimum" aperture. A recent graph in one of the threads indicates f5.6, not f8, was the optimum, regardless of the f1.4 or f2.8 max aperture...

08-08-2014, 02:27 PM	#11
ElJamoquio Veteran Member Join Date: Feb 2011 Posts: 4,873	Originally posted by lesmore49 I have some fast lenses...F 1.4, F 1.8, etc. I rarely shoot them at F 1.4, 1.8 due to sharpness. I think it's great to have an F 1.8....but if the sharpness ain't there (in my view) till about F 3.5....maybe F 2.8....I've never been able to see the value, especially for advanced amateur photography. I understand the bokeh thing. I wonder if...really fast lenses....say F 1.4 to F 1.8 at these F stops....are worth it, particularly in these days of ever increasing ISO....with ever decreasing noise....or grain as we used to call it. What's your view ? I like having F/1.8 available. F/1.4 or faster is rarely used. I'm debating purchasing vs renting a fast lens for use in ultra-low-light.

08-08-2014, 02:55 PM - 2 Likes	#12
Paul the Sunman Pentaxian Join Date: Aug 2011 Location: Melbourne Photos: Gallery Posts: 4,842	I do not criticize oil paintings because I can see the brush strokes. I do not criticize high iso film photos because I can see the grain. These are in the nature of the medium. It is the skill of the artist that uses the character of the medium to create an impression, a mood ... in short, art.

08-08-2014, 03:29 PM	#13
jrpower10 Site Supporter Join Date: Sep 2011 Location: Richland, Washington, USA Posts: 935	Seen this before and never seen anyone point out that, the faster the lens, the faster the optimal aperture probably is. If in general a lens hits peak sharpness about 2 stops from wide open, a 1.4 lens will be sharpest at 2.8, whereas a 2.8 lens will be sharpest at 5.6, etc. So, even though a fast lens is sharpest stopped down, so is virtually every other lens. My 31 limited is sharper at f4 than at f1.8, but that doesn't make it a bad lens, even wide open. It's sharper wide open than my 16-50 f2.8 wide open (OK apples and oranges, but you get the point). Some fast lenses probably aren't worth it because they just aren't that good, but a good fast lens is, IMHO.

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08-08-2014, 03:53 PM	#14
carrrlangas Veteran Member Join Date: Mar 2012 Location: Joensuu (Finland) Photos: Gallery Posts: 1,761	I don`t think any of the modern lenses is bad wide open. I think nailing focus and having enough depth of field are more relevant than how sharp the lens is wide open. I use the largest aperture keeping AF / DoF ok, as I find dynamic range suffers quite a bit from higher ISOs. I suspect there`s a problem with my PP workflow and/or my expectations.

08-08-2014, 04:00 PM	#15
Unregistered User Guest	Originally posted by Paul the Sunman I do not criticize oil paintings because I can see the brush strokes. I do not criticize high iso film photos because I can see the grain. These are in the nature of the medium. It is the skill of the artist that uses the character of the medium to create an impression, a mood ... in short, art. Some risible claptrap right there. The guy had a practical question; what he gets instead is pseudoprofound malarkey.