Sharpest fast 17mm lens?


dinneenp

Link Posted 04/10/2015 - 14:29
Hi
My Tamron 17-50 f2.8 lens is struggling these days, at 17mm won't focus automatically.
I'm planning on replacing it but would like to know which lens (17mm or thereabouts shortest focal length to 50mm or thereabouts ) would be the sharpest wide open/at f2.8?

Many reviews say x lens is soft wide open but one the points of such a lens is to use it wide open.
Thanks in advance,
Pa
Cheers,
Pa
http://www.photoblog.ie where every post have a musical reference as it's title.

Chrism8

Link Posted 04/10/2015 - 15:12
I continue to get excellent use and IQ from a Sigma 17-70 F2.8 coupled with a K5iis, its my general walkabout lens
Chris

www.chrismillsphotography.co.uk

" A Hangover is something that occupies the Head you neglected to use the night before".

-------------------------------------------------------------
K1 - Sigma 85mm F1.4, Pentax 150 -450 F4.5 / 5.6, Pentax FA 24 - 70 F2.8

Sigma 100-300 F4, Samyang 14mm F2.8, Sigma 70-200 F2.8,

K5iis - Sigma 17 - 70 F2.8, Sigma 70 - 300 F3.5/F5.6, Sigma 18 - 200 F3.6 / F4.5.

McGregNi

Link Posted 04/10/2015 - 18:12
Sometimes the point of a 'fast' lens is so that it's sharp stopped down a little ....
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver
Last Edited by McGregNi on 04/10/2015 - 18:14

50mpCMOS

Link Posted 05/10/2015 - 01:07
For possible replacements...

The Sigma 18-35mm f1.8 is one of the fastest focusing lenses that almost reaches that 17mm, yet not even close to what you were looking for in the more towards 50 range. Naturally, given the focal stop, it's quite incredible.

Then there's the Pentax DA* 16-50mm f2.8... But given the ever present issues that have plagued that very lens, throughout numerous factory runs... If one must purchase that lens and want to use it, also carry a spare lens - unless one truly likes going into manual settings.

The Pentax 12-24mm f4.o is also incredibly sharp and fast focusing, but also at a rather limited focal length range.

It all really depends upon what one is willing to sacrifice. Also noting that general starting range focal length, the sharpest lens wide open, but still a zoom would be limited in focal length range. For that limited range the Sigma 18-35 would still be the best bet

asharpe

Link Posted 05/10/2015 - 05:22
Indeed, the "normal" point of a wide lens is usually *not* to use it wide open; bokeh from fast normal and short telephoto lenses is usually much better. McGregNi's posting is on target; the reason to get a fast wide lens is so you can use it at a larger aperture and still get sharp photos, at a higher shutter speed and lower iso. So, instead of f8, perhaps f4 will be very good. There are very few lenses that are sharp wide open; even the ridiculously priced Otus is softer wide open.
Pentax K3 body (+KatzEye screen), Pentax K20D body (+KatzEye screen), Pentax Fisheye Takumar 17/4 (M42), Pentax Super Takumar 28/3.5 (M42), Pentax Takumar 35/3.5 (M42), Pentax Macro Takumar Preset 50/4 (M42), Pentax Super Takumar 50/1.4 (M42), Pentax Macro Takumar SMC 100/4 (M42), Pentax Takumar 135/3.5 Preset (M42), Pentax Takumar 200/5.6 Preset (M42), Sigma Super Wide II 24/2.8 (KA mount), Pentax-A 35/2.8 (KA), Pentax-A 50/1.7 (KA), Pentax-A 200/4 (KA), Vivitar Macro TC (KA), Pentax-F 35-70/3.5-4.5 (KAF), Pentax-F 50/1.7 (KAF), Takumar-F 70-200/4-5.6 (KAF), Gitzo 1542T

petrochemist

Link Posted 05/10/2015 - 14:05
asharpe wrote:
Indeed, the "normal" point of a wide lens is usually *not* to use it wide open; bokeh from fast normal and short telephoto lenses is usually much better. McGregNi's posting is on target; the reason to get a fast wide lens is so you can use it at a larger aperture and still get sharp photos, at a higher shutter speed and lower iso. So, instead of f8, perhaps f4 will be very good. There are very few lenses that are sharp wide open; even the ridiculously priced Otus is softer wide open.

The point of having variable aperture is to select the aperture appropriate for the shot. Yes the lens is not intended for use only wide open and sharpness will improve when stopped down. Comparison with the DOF & bokeh of normal/telephoto lenses is hardly relevant, they have a completely different FOV, and give very different compositions.

The OP suggests Pa has a need to use his lens at ~f2.8 & wants to know the sharpest options for that. Telling him to stop down is not going to solve his problem. If it's for shooting the night sky, bokeh will not normally be relevant & stopping down can cause a host of other issues (star trails/noise...).
Mike
.
Pentax:K5ii, K7, K100D, DA18-55, DA10-17, DA55-300, DA50-200, F100-300, F50, DA35 AL, 4* M50, 2* M135, Helicoid extension, Tak 300 f4 (& 6 film bodies)
3rd Party: Bigmos (Sigma 150-500mm OS HSM),2* 28mm, 100mm macro, 28-200 zoom, 35-80 zoom, 80-200 zoom, 80-210 zoom, 300mm M42, 600 mirror, 1000-4000 scope, 50mm M42, enlarger lenses, Sony & micro 4/3 cameras with various PK mounts, Zenit E...
Far to many tele-converters, adapters, project parts & extension tubes etc.

.[size=11:].Flickr WPF Panoramio

dinneenp

Link Posted 05/10/2015 - 14:47
Thanks for the replies so far. My Tamron 17-50 f2.8 is my everyday lens, I like that it has a bit of focal length and is quick. Obviously I don't always use it at f2.8 but was wondering which lens would be best for this.

The lens doesn't have to reach 50mm but it'd be nice. I wasn't aware that there is a Sigma 18-35 f1.8; focal length is shorter than others but, wow, what a good lens it sounds like. Just googled it and although not cheap it does sound like a dream. The Sigma 17-70 f2.8-f4 sounds more sensible for everyday use and it's good for close up (I created another thread asking about best 'general' fast lens that's better than my Tammy for close up. Although I think I might end up buying a Raynox adaptor.

I think I'll play around with my lenses; restrict to 35 mm and see if it's too restrictive (I know people can say move closer), use up to 70 mm but at relevant aperture the 17-70 lens has etc.

I like my quick lenes; my lens collection consists of a Sigma 30mm f1.4, Tamron 17-50 f2.8, Pentax 100mm f2.8 and Sigma 70-200 f2.8.
Cheers,
Pa
http://www.photoblog.ie where every post have a musical reference as it's title.

Horst

Link Posted 06/10/2015 - 09:11
What do you actually photograph with say a 17 or similar lens with f2.8 wide open.

Do you do landscapes, or interiors? Would the limited dof not be a problem?

I really never had any need to use anything faster then F 3.5 and this very seldom.

For landscapes , if it is to dark, a tripod replaces a fast f-stop .

But I may be totally wrong about all this and have overlooked something.

Regards, Horst

Smeggypants

Link Posted 06/10/2015 - 10:18
asharpe wrote:
Indeed, the "normal" point of a wide lens is usually *not* to use it wide open;

And

asharpe wrote:
McGregNi's posting is on target; the reason to get a fast wide lens is so you can use it at a larger aperture and still get sharp photos, at a higher shutter speed and lower iso.

For the Sharp freaks those two statements might be the "norm", but fortunately not every photographer is fixated on sharp sharp sharp.


There's so much more to photography than sharp sharp sharp.

Atleast Nigel had the sense to say that ....

McGregNi wrote:
Sometimes the point of a 'fast' lens is so that it's sharp stopped down a little ....

.... instead of claiming it's the norm.
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283

johnriley

Link Posted 06/10/2015 - 10:19
Horst wrote:
What do you actually photograph with say a 17 or similar lens with f2.8 wide open.

Do you do landscapes, or interiors? Would the limited dof not be a problem?

I really never had any need to use anything faster then F 3.5 and this very seldom.

For landscapes , if it is to dark, a tripod replaces a fast f-stop .

But I may be totally wrong about all this and have overlooked something.

Regards, Horst

It's a fair point. Wide angles are generally used stopped down, so fast speeds are not needed. As we can increase the ISO as well, there seems even less need for a fast wideangle.
Best regards, John

McGregNi

Link Posted 06/10/2015 - 11:16
I can understand that some may feel the 'need for speed' in low light, although these days surely far better high ISO performance than we could ever get on film would negate the super wide apertures as a real requirement .... ?

Where I would question it more though, is in the actual Depth Of Field effects that you can achieve at wide angles. It would be interesting to see some comparison shots of scenes taken at 17mm, shot at F2.8, and F3.5 and F4.0, just to see the real practical differences .....I suggest these would only be apparent at the most extreme close-focusing distances.
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver

dinneenp

Link Posted 06/10/2015 - 11:28
Good questions. I guess that the f2.8 would be more helpful at the far end of the focal length (50mm) rather than at the short length (17mm).
I don't really shot landscapes. Maybe I'm not thinking about it fully, just presuming that a fast lens is 'better' as it offers you more in low light and also for bokeh. The 18-135 looks like a nice lens even if it's not very fast.
I might even go down the route of buying a few lenses with the plan to play with them, try them out and sell them if I don't like them and buy a different lens. Rather than my current mind-set which is buying a lens for the long term. I would like to try out a 10-20mm lens, 17-70 (as a general lens), 18-135 (as a general lens), 50-135 f2.8, 35 f2.8 macro and more.....
Cheers,
Pa
http://www.photoblog.ie where every post have a musical reference as it's title.

johnriley

Link Posted 06/10/2015 - 12:11
Trying out lenses is wonderful fun! Every lens has its own characteristics, and lens tests only show (only can show) a small part of it. The rest is a question of whether or not the quirks of a particular lens suit the photographer's needs.
Best regards, John

LennyBloke

Link Posted 06/10/2015 - 12:35
johnriley wrote:
Trying out lenses is wonderful fun! Every lens has its own characteristics, and lens tests only show (only can show) a small part of it. The rest is a question of whether or not the quirks of a particular lens suit the photographer's needs.

That's precisely the way at look at "PentaxLife" ! Try as many different lenses as you can! Buy when you have a need/want for a particular type of photography, Sell when you move on to something else (to recoup your outlay) and along the way you'll find an odd lens or two that you find "special" and you'll keep them.

Admittedly this philosophy is flawed in my case - I find it hard to part with a lot of my lenses, consequently I have 60+ at present. I knew things were bad when I bought a lens a couple of weeks ago only to find I already had a copy in my collection
LennyBloke

Smeggypants

Link Posted 07/10/2015 - 02:02
McGregNi wrote:
I can understand that some may feel the 'need for speed' in low light, although these days surely far better high ISO performance than we could ever get on film would negate the super wide apertures as a real requirement .... ?

It's not a case of either/or where one negates the other. Having a fast lens AND good high ISO performance means even more options for even lower light shooting
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283
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