For Sale - Sold: Vivitar Series 1 90mm 2.5 Macro

Votesh · 05-31-2008, 11:24 PM

Originally posted by pentaxman

You can tell by looking at the pictures of the mount that it is not an "A" lens. It also says P/K on the mount - not P/KA. The other reason I know is that I have one just like it. It is an amazing lens. The barrel is anodized, not painted and is just beautiful.

This lens will go only to 1:2 without the macro adaptor. Of course, with the digital crop factor that works out to 1:1.3 I have never had a problem with this lens not focusing close enough.

Tom

Actually, even on a DSLR the magnification would still be 1:2. The crop factor only has an effect on the focal length of the lens, not the magnification.

marcusyoung · 06-01-2008, 07:34 AM

Originally posted by Okami

changed description and price + shipping.

May I know what is the latest price like?

marcus

Fl_Gulfer · 06-01-2008, 01:10 PM

I hope this lens is as good as you'all say, This is about all I need to fullfill my small kit.

**pentaxman** · 06-01-2008, 06:32 PM

I disagree - How can you change the focal length of the lens without changing the magnification?

Here is a close focus picture using my 105 F2.5. Notice that the full width of the frame is about 24mm. On a 35mm camera the full width would be 36mm. So on a APSC camera you can take a picture of something 24mm wide and it will take the full width of the frame.

Here is a close focus picture using my 90 F2.5. Notice that the full width of the frame is about 48mm. On a 35mm camera the full width would be 72mm. So on a APSC camera you can take a picture of something 48mm wide and it will take the full width of the frame.

I see your point though 1:1 means life size on film. Since the APSC sensor is only 24mm, then something 24mm wide is only 1:1 on APSC. Come to think of it, you are actually right. But you do get more apparent magnification with an APSC camera.

Originally posted by Votesh

Actually, even on a DSLR the magnification would still be 1:2. The crop factor only has an effect on the focal length of the lens, not the magnification.

Last edited by pentaxman; 06-01-2008 at 07:23 PM.

creampuff · 06-01-2008, 07:20 PM

Originally posted by pentaxman

I disagree - How can you change the focal length of the lens without changing the magnification?

The focal length of the lens has not changed, neither has the magnification ratio. The apparent FOV has been reduced due to the crop factor, that's all.

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05-31-2008, 11:24 PM	#16
Votesh Inactive Account Join Date: Apr 2008 Posts: 817 Feedback Score: 28 (100%)	Originally posted by pentaxman You can tell by looking at the pictures of the mount that it is not an "A" lens. It also says P/K on the mount - not P/KA. The other reason I know is that I have one just like it. It is an amazing lens. The barrel is anodized, not painted and is just beautiful. This lens will go only to 1:2 without the macro adaptor. Of course, with the digital crop factor that works out to 1:1.3 I have never had a problem with this lens not focusing close enough. Tom Actually, even on a DSLR the magnification would still be 1:2. The crop factor only has an effect on the focal length of the lens, not the magnification.

06-01-2008, 07:34 AM	#17
marcusyoung Veteran Member Join Date: May 2007 Location: singapore Posts: 1,123 Feedback Score: 2 (100%)	Originally posted by Okami changed description and price + shipping. May I know what is the latest price like? marcus

06-01-2008, 01:10 PM	#18
Fl_Gulfer Veteran Member Join Date: Jul 2007 Location: Florida Gulfer Posts: 3,054 Feedback Score: 57 (100%)	I hope this lens is as good as you'all say, This is about all I need to fullfill my small kit.

06-01-2008, 06:32 PM	#19
pentaxman Site Supporter Join Date: Oct 2007 Location: Washington Posts: 250 Feedback Score: 30 (100%)	I disagree - How can you change the focal length of the lens without changing the magnification? Here is a close focus picture using my 105 F2.5. Notice that the full width of the frame is about 24mm. On a 35mm camera the full width would be 36mm. So on a APSC camera you can take a picture of something 24mm wide and it will take the full width of the frame. Here is a close focus picture using my 90 F2.5. Notice that the full width of the frame is about 48mm. On a 35mm camera the full width would be 72mm. So on a APSC camera you can take a picture of something 48mm wide and it will take the full width of the frame. I see your point though 1:1 means life size on film. Since the APSC sensor is only 24mm, then something 24mm wide is only 1:1 on APSC. Come to think of it, you are actually right. But you do get more apparent magnification with an APSC camera. Originally posted by Votesh Actually, even on a DSLR the magnification would still be 1:2. The crop factor only has an effect on the focal length of the lens, not the magnification. Last edited by pentaxman; 06-01-2008 at 07:23 PM.

06-01-2008, 07:20 PM	#20
creampuff Veteran Member Join Date: May 2007 Location: Singapore Posts: 3,953 Feedback Score: 13 (100%)	Originally posted by pentaxman I disagree - How can you change the focal length of the lens without changing the magnification? The focal length of the lens has not changed, neither has the magnification ratio. The apparent FOV has been reduced due to the crop factor, that's all.