SMC PENTAX-F 1:1.7 50mm vs fixed aperture zoom lens?
Posted 31/08/2010 - 17:34
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I find the 50mm on a crop sensor dslr is a bit long , good for portraits.
I have the sigma 17-70mm f2.8-4.5 and find it a great range for a walk about lens.
I rarely find my self needing anything any wider than 17mm or longer than 70mm, wish it was a bit faster for low light stuff but then it would cost alot more.
Modern zooms are very good , i've been very impressed with both the Pentax 18-55mm wr and the Sigma 17-70mm
I have the sigma 17-70mm f2.8-4.5 and find it a great range for a walk about lens.
I rarely find my self needing anything any wider than 17mm or longer than 70mm, wish it was a bit faster for low light stuff but then it would cost alot more.
Modern zooms are very good , i've been very impressed with both the Pentax 18-55mm wr and the Sigma 17-70mm
Posted 01/09/2010 - 14:41
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I have the Tamron 17-50 which has performed very well for me. Colours are perhaps a tad cooler than Pentax lenses, but it's nice and sharp. Pretty good wide open up to maximum sharpness at around f5.6.
Tim
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27”, Macbook Pro 17”, iPad, iPhone 3G
Flickr • Fluidr • PPG • Street • Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!
AF - Pentax K5, Sigma 10-20/4-5.6, Tamron 17-50/2.8, Sigma 30/1.4, Sigma 70-200/2.8, Tamron 70-300/4-5.6
MF - Vivitar CF 28/2.8, Tamron AD2 90/2.5, MTO 1000/11
Stuff - Metz 58 AF1, Cactus v4, Nikon SB24, Raynox 150, Sigma 1.4x TC, Sigma 2x TC, Kenko 2x macro TC, Redsnapper 283 tripod, iMac 27”, Macbook Pro 17”, iPad, iPhone 3G
Flickr • Fluidr • PPG • Street • Portfolio site
Feel free to edit any of my posted photos! If I post a photo for critique, I want brutal honesty. If you don't like it, please say so and tell me why!
Posted 01/09/2010 - 15:39
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dinneenp wrote:
Hi,
I have a SMC PENTAX-F 1:1.7 50mm lens, find the length too long.
Thinking of swapping for a fixed aperture (2.8 probably) zoom (Sigma 17-70, Tarmon 17-50 or similar).
Pluses- zoom.
Minuses-physical size & weight, aperture.
What do you think, which would you prefer etc?
cheers,
pa.
Hi,
I have a SMC PENTAX-F 1:1.7 50mm lens, find the length too long.
Thinking of swapping for a fixed aperture (2.8 probably) zoom (Sigma 17-70, Tarmon 17-50 or similar).
Pluses- zoom.
Minuses-physical size & weight, aperture.
What do you think, which would you prefer etc?
cheers,
pa.
Sigma 17-50/2.8 has a fixed aperture, 17-70 doesn't. I guess it's very much up to your style of photographing. Personally, I would keep the fifty even if I bought a fast zoom lens.
Link to my PPG
Posted 01/09/2010 - 15:47
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I can't comment on either of these lenses because I have no experience of them.
What I do know however is that they are not known as 'fixed aperture' lenses. The correct term is 'constant aperture', that is if the lens is set to f11 at one extreme of it's zoom range, it will remain at f11 throught the entire range.
The term 'fixed aperture' applies to lenses like the various 500mm mirror lenses which have their aperture fixed at f8, or similar, and can only be changed by the addition of ND filters.
BTW: The SMC Pentax DA* 16-50mm 1:2.8 lens is a constant aperture zoom lens and produces excellent results.
What I do know however is that they are not known as 'fixed aperture' lenses. The correct term is 'constant aperture', that is if the lens is set to f11 at one extreme of it's zoom range, it will remain at f11 throught the entire range.
The term 'fixed aperture' applies to lenses like the various 500mm mirror lenses which have their aperture fixed at f8, or similar, and can only be changed by the addition of ND filters.
BTW: The SMC Pentax DA* 16-50mm 1:2.8 lens is a constant aperture zoom lens and produces excellent results.
Peter E Smith - flickr Photostream
Posted 01/09/2010 - 15:48
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Do Tamron do their 17-50 in a Pentax mount?
Barrie - Too Old To Die Young
https://pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/
https://pentaxphotogallery.com/artists/barrieforbes
https://www.flickr.com/photos/189482630@N03/
Posted 01/09/2010 - 23:45
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Mannesty wrote:
The term 'fixed aperture' applies to lenses like the various 500mm mirror lenses which have their aperture fixed at f8, or similar, and can only be changed by the addition of ND filters.
The term 'fixed aperture' applies to lenses like the various 500mm mirror lenses which have their aperture fixed at f8, or similar, and can only be changed by the addition of ND filters.
Peter I'm having troubles to understand how a ND filter can alter the aperture, could you please enlighten me?
Posted 01/09/2010 - 23:48
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bforbes wrote:
Do Tamron do their 17-50 in a Pentax mount?
Do Tamron do their 17-50 in a Pentax mount?
For quite sometimes as far as I know
Sigma also has now a 17-50 f/2.8 EX OS HSM for Pentax link
Here is a review link
Was thinking about getting that one instead of the DA*16-50 but the Sigma wasn't out yet but IQ wise the Sigma has the same weak wide open at wide focal length preformance so not disappointed I didn't wait for it.
Posted 02/09/2010 - 05:45
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Anvh wrote:
Peter I'm having troubles to understand how a ND filter can alter the aperture, could you please enlighten me?
Mannesty wrote:
The term 'fixed aperture' applies to lenses like the various 500mm mirror lenses which have their aperture fixed at f8, or similar, and can only be changed by the addition of ND filters.
The term 'fixed aperture' applies to lenses like the various 500mm mirror lenses which have their aperture fixed at f8, or similar, and can only be changed by the addition of ND filters.
Peter I'm having troubles to understand how a ND filter can alter the aperture, could you please enlighten me?
I think he means that by adding ND filters you can lower the amount of light passing through the lens, i.e. "changing the f value".
Link to my PPG
Posted 02/09/2010 - 08:38
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flat4 wrote:
I think he means that by adding ND filters you can lower the amount of light passing through the lens, i.e. "changing the f value".
Anvh wrote:
Peter I'm having troubles to understand how a ND filter can alter the aperture, could you please enlighten me?
Quote:
The term 'fixed aperture' applies to lenses like the various 500mm mirror lenses which have their aperture fixed at f8, or similar, and can only be changed by the addition of ND filters.
The term 'fixed aperture' applies to lenses like the various 500mm mirror lenses which have their aperture fixed at f8, or similar, and can only be changed by the addition of ND filters.
Peter I'm having troubles to understand how a ND filter can alter the aperture, could you please enlighten me?
I think he means that by adding ND filters you can lower the amount of light passing through the lens, i.e. "changing the f value".
Exactly right. Some mirror lenses are supplied with ND filters for this purpose from new.
Technically the aperture doesn't change of course, but the effect of adding an ND filter is to attenuate the light in bright conditions. Bokeh and DOF remain unchanged.
Peter E Smith - flickr Photostream
Posted 02/09/2010 - 17:51
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Thank you Peter to enlighten that bit, I was under the impression you meant it changed the f-ratio and therefore also the DOF.
Are there any ways to control the aperture with mirror lenses?
Are there any ways to control the aperture with mirror lenses?
Posted 02/09/2010 - 18:00
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Quote:
Are there any ways to control the aperture with mirror lenses?
Are there any ways to control the aperture with mirror lenses?
No, the aperture is fixed. However, because of the zooming the aperture of the Pentax 400-600mm does change.
Best regards, John
Posted 02/09/2010 - 18:26
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Aren't there ways to make the opening smaller like a diaphragm does, maybe in form off a filter or will that give vignetting?
Just a little point, do you really mean aperture or the f-number?
Those are two different things and one change with zooming alone but the other needs physical changing so I'm not sure which you mean.
Edit: make a mistake myself.
johnriley wrote:
No, the aperture is fixed. However, because of the zooming the aperture of the Pentax 400-600mm does change.
No, the aperture is fixed. However, because of the zooming the aperture of the Pentax 400-600mm does change.
Just a little point, do you really mean aperture or the f-number?
Those are two different things and one change with zooming alone but the other needs physical changing so I'm not sure which you mean.
Edit: make a mistake myself.
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14 years
I have a SMC PENTAX-F 1:1.7 50mm lens, find the length too long.
Thinking of swapping for a fixed aperture (2.8 probably) zoom (Sigma 17-70, Tarmon 17-50 or similar).
Pluses- zoom.
Minuses-physical size & weight, aperture.
What do you think, which would you prefer etc?
cheers,
pa.
Pa
http://www.photoblog.ie where every post have a musical reference as it's title.