Canon 50mm MkI loses optical sharpness at F1.8 than at F2-F4?

Henry Low · 15th of December 2004 (Wed)

Hi there, i just got my hands on a 50mm MkI F1.8 lens mint condition. I noticed that when i take pictures of computer fonts on a document paper, i played around with the aperture sizes... i noticed that at F1.8, the optical sharpness( not caused by shake), is not as good as... say F2 or F4... is that a normal thing with this lens? I made sure the camera didnt shake by puttng it on a tripod and using the timer function

thanks in advance

Olegis · 15th of December 2004 (Wed)

All (well, almost all) lenses become softer wide open, it's pretty normal. Your 50mm behavior is perfectly normal.

Andy_T · 15th of December 2004 (Wed)

Take a look at this comparison here:
http://www.photo.net/equipment/canon/ef50/

You will notice that the 1.4/50 is a little sharper at f/2.0 than the 1.8/50.

This is mainly because the 1.4/50 will be stopped down a bit if you use it at 2.0.

Best regards,
Andy

tim · 15th of December 2004 (Wed)

Take a look at this thread I posted yesterday. I'll update it on the weekend to have more shots at the lower end of the scale for both lenses, and also to include the Tamron 28-75 and the kit lens.

Cadwell · 15th of December 2004 (Wed)

Most lenses are a little soft wide open. Don't worry about it.

Artur Gajewski · 15th of December 2004 (Wed)

I have this lens as well and I have noticed that the best sharpness is obtained by using the F2.8 setting. I hardly use any other, except when I need shallow DOF or to photograph in dark without flash.

15th of December 2004 (Wed)	#1
Henry Low Member Join Date: Oct 2004 Location: Vancouver BC, CANADA! Posts: 408	Canon 50mm MkI loses optical sharpness at F1.8 than at F2-F4? Hi there, i just got my hands on a 50mm MkI F1.8 lens mint condition. I noticed that when i take pictures of computer fonts on a document paper, i played around with the aperture sizes... i noticed that at F1.8, the optical sharpness( not caused by shake), is not as good as... say F2 or F4... is that a normal thing with this lens? I made sure the camera didnt shake by puttng it on a tripod and using the timer function thanks in advance

15th of December 2004 (Wed)	#2
Olegis Goldmember Join Date: Apr 2004 Location: Israel Posts: 2,073	Re: Canon 50mm MkI loses optical sharpness at F1.8 than at F2-F4? All (well, almost all) lenses become softer wide open, it's pretty normal. Your 50mm behavior is perfectly normal. __________________ Best wishes, Oleg. www.Olegis.com My equipment list 'I take orders from no one except the photographers' – Harry S Truman

15th of December 2004 (Wed)	#3
Andy_T Compensating for his small ... sensor Join Date: Jan 2003 Location: Stuttgart/Cologne, Germany Posts: 9,848 IMAGE EDITING OK	Re: Canon 50mm MkI loses optical sharpness at F1.8 than at F2-F4? Take a look at this comparison here: http://www.photo.net/equipment/canon/ef50/ You will notice that the 1.4/50 is a little sharper at f/2.0 than the 1.8/50. This is mainly because the 1.4/50 will be stopped down a bit if you use it at 2.0. Best regards, Andy __________________ some cameras, some lenses, and still a lot of things to learn... (so post processing examples on my images are welcome ) If you like the forum, vote for it where it really counts! CLICK here for the EOS FAQ CLICK here for the Post Processing FAQ CLICK here to understand a bit more about BOKEH

15th of December 2004 (Wed)	#4
tim Light Bringer Join Date: Nov 2004 Location: Wellington, New Zealand Posts: 47,899 IMAGE EDITING OK	Re: Canon 50mm MkI loses optical sharpness at F1.8 than at F2-F4? Take a look at this thread I posted yesterday. I'll update it on the weekend to have more shots at the lower end of the scale for both lenses, and also to include the Tamron 28-75 and the kit lens. __________________ NZIPP Qualified Professional wedding photographer. Camera and Lens Reviews ~ Wellington Wedding Photographer Wellington Wedding Photographer (site2) ~ Wellington Wedding Photographer (site3) Read all my FAQs (wedding, printing, lighting, books, etc)

15th of December 2004 (Wed)	#5
Cadwell Moderator Join Date: Jan 2004 Location: Hampshire, UK Posts: 7,333	Re: Canon 50mm MkI loses optical sharpness at F1.8 than at F2-F4? Most lenses are a little soft wide open. Don't worry about it. __________________ Glenn My Pictures: Motorsport/Canoe Polo/Other Stuff

15th of December 2004 (Wed)	#6
Artur Gajewski Junior Member Join Date: Sep 2004 Location: Helsinki, Finland Posts: 21	Re: Canon 50mm MkI loses optical sharpness at F1.8 than at F2-F4? I have this lens as well and I have noticed that the best sharpness is obtained by using the F2.8 setting. I hardly use any other, except when I need shallow DOF or to photograph in dark without flash. __________________ - Artur Canon EOS 300D Kit + EF 50mm/1.8 + Sigma 28-300 + Sigma EF-500 DG Super World in my eyes - My gallery Last edited by Artur Gajewski : 15th of December 2004 (Wed) at 06:33.

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