Tamron 17-50mm (and other lens) observations on MZ-7

DaveHolmes · 01-26-2012, 06:06 AM

I had planed on using my F35-70 on my MZ-7... But I thought I'd try all my AF lenses on it with the first roll of film (still to be developed..)

(NB: my opinions/observances are subject purely to my view through the viewfinder, as I have yet to develop any film from the MZ-7...)

Love the FA50 especially in 'pano' mode... (can see this as normal outing combo along with K-x & FA28 but may look out for an F50-1.7 specifically for the MZ-7).. The FA just looks 'better' (not just sharp but vivid, more saturated) than the F35-70... Is that even possible? Just how the viewfinder image appears in my eye (the right one)...

But the Tamron 17-50mm-2.8 was what shocked me a little... I've never seen much in the way of (curving) distortion when I've used it on the K-x... Although it is what I consider VERY wide on the MZ-7 (in fact the widest FoV I have on any camera currently...) it definitely carries some fair evident distortion of perspective

Also, there appears to be slight vignetting (or at least a darkening) of corners using the 17-50 on the MZ-7... What causes this? Is it because the lens is designed for aps-c?

stanislav · 01-26-2012, 08:08 AM

There is deffinitly difference in full-frame lenses and those designed for aps-c size and the difference is not just in the field of view (FoV).

You should bear in mind that aps-c size iz something like 24x16mm (or slightly less) whereas FF is 36x24mm. With some failry simple math it ends up that the FF lens projects the picture on a circle of diameter of at least 43.25mm (to cover the film plane), whereas in the case of aps-s it is enough to have projection of radius of 28.85mm which is 2/3 of the FF radius. In that case the corners are darkened and if fall-off is abrupt what you would get is basically a projection of a circle on the film.

Now the size of projection circle is depending even on the focus point and in case it is a zoom lens of the zoom. Most zoom lenses simply project the picture on the larger circle (generally speaking) so that simplification of your tamron 17-50 is something like this: at 17mm the projected circle is at least 28.85mm, and it grows with the zoom so that the circle is 3 times as big at 50mm. As I said it is a simplification but in a case of aps-c lenses on FF it is a good one.

So vigneting of your tamron should stop at 17mm*1.5 = 25.5mm which is the widest focal length that you can be shure that the lens is going to perform as you expect. Moreover the FoV at 25.5mm on FF should be equal to FoV at 17mm on aps-c.

Now I have to say that I don't have tamron 17-50, but I did some test with sigma 10-20. It was vigneting untill somewhere between 13-14mm and performed rather well passed that.

stevebrot · 01-27-2012, 09:29 PM

Originally posted by DaveHolmes

Also, there appears to be slight vignetting (or at least a darkening) of corners using the 17-50 on the MZ-7... What causes this? Is it because the lens is designed for aps-c?

Yep...

APS-C lenses have smaller coverage circle than lenses designed for full-frame 35mm.

Steve

fraction · 09-24-2012, 06:28 AM

Could you post up some samples?

I've just bought myself a tammy 17-50 and was wondering what it would do on a film body!

DaveHolmes · 09-24-2012, 07:08 AM

Originally posted by fraction

Could you post up some samples?
I've just bought myself a tammy 17-50 and was wondering what it would do on a film body!

I've actually just sold the Tammy to fund K5 purchase...

These were with Tamron 17-50 on MZ-7 with Fuji Superior 400... The vignetting is pronounced on one side - this could be something to do with the lab that processed and scanned them(?)

All taken in Northside Tattoo - Newcastle-Upon-Tyne

fraction · 09-24-2012, 07:27 AM

Wow, cheers! They have a really weird vignetting, I kinda like it

DaveHolmes · 09-24-2012, 08:09 AM

Originally posted by fraction

Wow, cheers! They have a really weird vignetting,

Yep. And note... I have done 'no' post production or crops on these images... They're how they were picked up on disk from the lab...

stanislav · 09-26-2012, 06:01 AM

This vignetting seem to have shape of the lens hood (more so on wide angle), so out of curiosity, did you have the lens hood on while taking these photos?

stevebrot · 09-26-2012, 07:26 AM

Originally posted by stanislav

This vignetting seem to have shape of the lens hood (more so on wide angle), so out of curiosity, did you have the lens hood on while taking these photos?

Good observation

DaveHolmes · 09-26-2012, 12:52 PM

Originally posted by stanislav

This vignetting seem to have shape of the lens hood (more so on wide angle), so out of curiosity, did you have the lens hood on while taking these photos?

Yep... Tamron hood was indeed on.

01-26-2012, 06:06 AM	#1
DaveHolmes Veteran Member Join Date: Jul 2010 Location: Yorkshire Posts: 1,501	Tamron 17-50mm (and other lens) observations on MZ-7 I had planed on using my F35-70 on my MZ-7... But I thought I'd try all my AF lenses on it with the first roll of film (still to be developed..) (NB: my opinions/observances are subject purely to my view through the viewfinder, as I have yet to develop any film from the MZ-7...) Love the FA50 especially in 'pano' mode... (can see this as normal outing combo along with K-x & FA28 but may look out for an F50-1.7 specifically for the MZ-7).. The FA just looks 'better' (not just sharp but vivid, more saturated) than the F35-70... Is that even possible? Just how the viewfinder image appears in my eye (the right one)... But the Tamron 17-50mm-2.8 was what shocked me a little... I've never seen much in the way of (curving) distortion when I've used it on the K-x... Although it is what I consider VERY wide on the MZ-7 (in fact the widest FoV I have on any camera currently...) it definitely carries some fair evident distortion of perspective Also, there appears to be slight vignetting (or at least a darkening) of corners using the 17-50 on the MZ-7... What causes this? Is it because the lens is designed for aps-c?

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01-26-2012, 08:08 AM	#2
stanislav Senior Member Join Date: Jan 2010 Location: Stockholm Photos: Albums Posts: 125	There is deffinitly difference in full-frame lenses and those designed for aps-c size and the difference is not just in the field of view (FoV). You should bear in mind that aps-c size iz something like 24x16mm (or slightly less) whereas FF is 36x24mm. With some failry simple math it ends up that the FF lens projects the picture on a circle of diameter of at least 43.25mm (to cover the film plane), whereas in the case of aps-s it is enough to have projection of radius of 28.85mm which is 2/3 of the FF radius. In that case the corners are darkened and if fall-off is abrupt what you would get is basically a projection of a circle on the film. Now the size of projection circle is depending even on the focus point and in case it is a zoom lens of the zoom. Most zoom lenses simply project the picture on the larger circle (generally speaking) so that simplification of your tamron 17-50 is something like this: at 17mm the projected circle is at least 28.85mm, and it grows with the zoom so that the circle is 3 times as big at 50mm. As I said it is a simplification but in a case of aps-c lenses on FF it is a good one. So vigneting of your tamron should stop at 17mm*1.5 = 25.5mm which is the widest focal length that you can be shure that the lens is going to perform as you expect. Moreover the FoV at 25.5mm on FF should be equal to FoV at 17mm on aps-c. Now I have to say that I don't have tamron 17-50, but I did some test with sigma 10-20. It was vigneting untill somewhere between 13-14mm and performed rather well passed that.

01-27-2012, 09:29 PM	#3
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by DaveHolmes Also, there appears to be slight vignetting (or at least a darkening) of corners using the 17-50 on the MZ-7... What causes this? Is it because the lens is designed for aps-c? Yep... APS-C lenses have smaller coverage circle than lenses designed for full-frame 35mm. Steve

09-24-2012, 06:28 AM	#4
fraction New Member Join Date: Sep 2012 Posts: 5	Could you post up some samples? I've just bought myself a tammy 17-50 and was wondering what it would do on a film body!

09-24-2012, 07:08 AM	#5
DaveHolmes Veteran Member Join Date: Jul 2010 Location: Yorkshire Posts: 1,501 Original Poster	Originally posted by fraction Could you post up some samples? I've just bought myself a tammy 17-50 and was wondering what it would do on a film body! I've actually just sold the Tammy to fund K5 purchase... These were with Tamron 17-50 on MZ-7 with Fuji Superior 400... The vignetting is pronounced on one side - this could be something to do with the lab that processed and scanned them(?) All taken in Northside Tattoo - Newcastle-Upon-Tyne

09-24-2012, 07:27 AM	#6
fraction New Member Join Date: Sep 2012 Posts: 5	Wow, cheers! They have a really weird vignetting, I kinda like it

09-24-2012, 08:09 AM	#7
DaveHolmes Veteran Member Join Date: Jul 2010 Location: Yorkshire Posts: 1,501 Original Poster	Originally posted by fraction Wow, cheers! They have a really weird vignetting, Yep. And note... I have done 'no' post production or crops on these images... They're how they were picked up on disk from the lab...

09-26-2012, 06:01 AM	#8
stanislav Senior Member Join Date: Jan 2010 Location: Stockholm Photos: Albums Posts: 125	This vignetting seem to have shape of the lens hood (more so on wide angle), so out of curiosity, did you have the lens hood on while taking these photos?

09-26-2012, 07:26 AM	#9
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by stanislav This vignetting seem to have shape of the lens hood (more so on wide angle), so out of curiosity, did you have the lens hood on while taking these photos? Good observation

09-26-2012, 12:52 PM	#10
DaveHolmes Veteran Member Join Date: Jul 2010 Location: Yorkshire Posts: 1,501 Original Poster	Originally posted by stanislav This vignetting seem to have shape of the lens hood (more so on wide angle), so out of curiosity, did you have the lens hood on while taking these photos? Yep... Tamron hood was indeed on.

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