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stevebrot · 04-01-2018, 04:15 PM

Originally posted by RKKS08

There were threads stating contrast of the M and A 1.4 will significantly improve if you put a filter reduction ring (49mm -> 46mm) on front of the lens. So the visible softness will be mostly gone.

On 35mm film, FF digital, or APS-C digital?

Adding a reducing ring acts as a hood (think MH-RC 49mm for the DA 40/2.8 Limited) on APS-C and adding a hood usually helps some with contrast. I routinely run a fairly deep hood on my fast-50s on APS-C, but have not seen any miracles with f/1.4 glass.

Steve

Jonathan Mac · 04-02-2018, 12:41 AM

Originally posted by stevebrot

On 35mm film, FF digital, or APS-C digital?

Adding a reducing ring acts as a hood (think MH-RC 49mm for the DA 40/2.8 Limited) on APS-C and adding a hood usually helps some with contrast. I routinely run a fairly deep hood on my fast-50s on APS-C, but have not seen any miracles with f/1.4 glass.

Steve

I remember this and it was on an APS-C camera. I had a search for the reducer ring but didn't find one and haven't bothered using several to do the same job. I think it was from 49mm to 32, a very significant drop. It's essentially acting as a deep hood, so maybe some of the sharpness and contrast reduction is due to flare of some type.

**GUB** · 04-02-2018, 01:01 AM

Originally posted by Jonathan Mac

I remember this and it was on an APS-C camera. I had a search for the reducer ring but didn't find one and haven't bothered using several to do the same job. I think it was from 49mm to 32, a very significant drop. It's essentially acting as a deep hood, so maybe some of the sharpness and contrast reduction is due to flare of some type.

Well you need at least 36mm to sustain f1.4 (50 / 1.4 ) so if you used 32mm you have stopped down to f1.6 just like using the iris.

**pres589** · 04-02-2018, 06:56 AM

Can you stop down that way? I'm not so wise but this seems like it would just vignette.

**GUB** · 04-02-2018, 01:03 PM

Originally posted by pres589

Can you stop down that way? I'm not so wise but this seems like it would just vignette.

Yes so long as it is close to the element - as you get further away then vignetting rather than stopping down gradually takes over. This varies with focal length and lens design but a 50 wide open would definitely stop down rather than vignette this way.

**pres589** · 04-02-2018, 01:20 PM

Ah, okay. I'm using a 55 to 49mm step-down ring on a Kiron 28mm f2.0 and didn't notice any such change on APS-C digital. Now I've using it on full frame film and am wondering how much it is affecting things. I really like having as much of my lens collection as possible using 49mm caps, filters, and screw-on hoods where possible...

**GUB** · 04-02-2018, 02:34 PM

Originally posted by pres589

Ah, okay. I'm using a 55 to 49mm step-down ring on a Kiron 28mm f2.0 and didn't notice any such change on APS-C digital. Now I've using it on full frame film and am wondering how much it is affecting things. I really like having as much of my lens collection as possible using 49mm caps, filters, and screw-on hoods where possible...

28s tend to vignette even when it is on the glass. It is to do with the focal length and I think to do with design - so it will be obvious if it is too tight.
There is a heck of a difference on FF with the 28mm. I have resorted to just using a filter ring with the glass smashed out for a hood!. I bought a cheap shaped hood but the internal shoulder of the filter thread was large enough to vignette the corners.

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04-01-2018, 04:15 PM	#31
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by RKKS08 There were threads stating contrast of the M and A 1.4 will significantly improve if you put a filter reduction ring (49mm -> 46mm) on front of the lens. So the visible softness will be mostly gone. On 35mm film, FF digital, or APS-C digital? Adding a reducing ring acts as a hood (think MH-RC 49mm for the DA 40/2.8 Limited) on APS-C and adding a hood usually helps some with contrast. I routinely run a fairly deep hood on my fast-50s on APS-C, but have not seen any miracles with f/1.4 glass. Steve

04-02-2018, 12:41 AM	#32
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,911	Originally posted by stevebrot On 35mm film, FF digital, or APS-C digital? Adding a reducing ring acts as a hood (think MH-RC 49mm for the DA 40/2.8 Limited) on APS-C and adding a hood usually helps some with contrast. I routinely run a fairly deep hood on my fast-50s on APS-C, but have not seen any miracles with f/1.4 glass. Steve I remember this and it was on an APS-C camera. I had a search for the reducer ring but didn't find one and haven't bothered using several to do the same job. I think it was from 49mm to 32, a very significant drop. It's essentially acting as a deep hood, so maybe some of the sharpness and contrast reduction is due to flare of some type.

04-02-2018, 01:01 AM	#33
GUB Loyal Site Supporter Join Date: Aug 2012 Location: Wanganui Photos: Gallery \| Albums Posts: 5,760	Originally posted by Jonathan Mac I remember this and it was on an APS-C camera. I had a search for the reducer ring but didn't find one and haven't bothered using several to do the same job. I think it was from 49mm to 32, a very significant drop. It's essentially acting as a deep hood, so maybe some of the sharpness and contrast reduction is due to flare of some type. Well you need at least 36mm to sustain f1.4 (50 / 1.4 ) so if you used 32mm you have stopped down to f1.6 just like using the iris.

04-02-2018, 06:56 AM	#34
pres589 Site Supporter Join Date: Jan 2014 Location: Wichita, KS Photos: Albums Posts: 4,533	Can you stop down that way? I'm not so wise but this seems like it would just vignette.

04-02-2018, 01:03 PM	#35
GUB Loyal Site Supporter Join Date: Aug 2012 Location: Wanganui Photos: Gallery \| Albums Posts: 5,760	Originally posted by pres589 Can you stop down that way? I'm not so wise but this seems like it would just vignette. Yes so long as it is close to the element - as you get further away then vignetting rather than stopping down gradually takes over. This varies with focal length and lens design but a 50 wide open would definitely stop down rather than vignette this way.

04-02-2018, 01:20 PM	#36
pres589 Site Supporter Join Date: Jan 2014 Location: Wichita, KS Photos: Albums Posts: 4,533	Ah, okay. I'm using a 55 to 49mm step-down ring on a Kiron 28mm f2.0 and didn't notice any such change on APS-C digital. Now I've using it on full frame film and am wondering how much it is affecting things. I really like having as much of my lens collection as possible using 49mm caps, filters, and screw-on hoods where possible...

04-02-2018, 02:34 PM	#37
GUB Loyal Site Supporter Join Date: Aug 2012 Location: Wanganui Photos: Gallery \| Albums Posts: 5,760	Originally posted by pres589 Ah, okay. I'm using a 55 to 49mm step-down ring on a Kiron 28mm f2.0 and didn't notice any such change on APS-C digital. Now I've using it on full frame film and am wondering how much it is affecting things. I really like having as much of my lens collection as possible using 49mm caps, filters, and screw-on hoods where possible... 28s tend to vignette even when it is on the glass. It is to do with the focal length and I think to do with design - so it will be obvious if it is too tight. There is a heck of a difference on FF with the 28mm. I have resorted to just using a filter ring with the glass smashed out for a hood!. I bought a cheap shaped hood but the internal shoulder of the filter thread was large enough to vignette the corners.

50 mm f1.4

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