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Occasional Contributor
Posts: 22
Registered: ‎04-16-2020

Lens, Meet Mirror

I'm back in the camera pool after 20 years of hating digital. I love my EOS 7T (baby steps) and enjoy using Takumar and other M42 lenses with it.

 

Does anyone know which old lenses have a problem with rear element intrusion? Takumars and their M42 clones seem pretty trouble free. I've read that others require a lens in the adapter body, presumably to kick the focus back to the sensor, and that seems too clunky for me but I'm concerned with the opposite case of element hitting mirror.

 

Thanks for any thoughts!

 

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Posts: 6,591
Registered: ‎11-13-2012

Re: Lens, Meet Mirror

You might want to post to the Adapted Lens Talk forum on DPReview.

John Hoffman
Conway, NH

1D X Mark III, Rebel T5i, Many lenses, Pixma PRO-100, MX472, LR Classic
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Re: Lens, Meet Mirror

[ Edited ]

@Quiet wrote:

I'm back in the camera pool after 20 years of hating digital. I love my EOS 7T (baby steps) and enjoy using Takumar and other M42 lenses with it.

 

Does anyone know which old lenses have a problem with rear element intrusion? Takumars and their M42 clones seem pretty trouble free. I've read that others require a lens in the adapter body, presumably to kick the focus back to the sensor, and that seems too clunky for me but I'm concerned with the opposite case of element hitting mirror.

 

Thanks for any thoughts!

 


Your issue seems to be a non-issue to me.  

 

Seeing how all M42 to EF mount adapters are designed to work with full frame bodies, your concerns about hitting the mirror are misplaced.  None of the older lenses were designed like EF-S lenses, anyway.  Even it you do encounter one, you appear to be using an APS-C body.  In other words, these imaginary concerns woul only apply to full frame bodies.

 

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Re: Lens, Meet Mirror

I have used many different film era manual focus lenses with adapters on my Canon DSLRs, and it is only the larger mirrors of Full Frame cameras that can have a problem with hitting the mirror.  This usually happenss with shorter focal lenth lenses when the rear element moves back in order to reach infinty focus. 

 

Because the T7 is a crop camera,  I can't think of any lens combination that would interfere with the mirror.

 

Mike Sowsun
S110, SL1, 80D, 5D Mk III
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Posts: 22
Registered: ‎04-16-2020

Re: Lens, Meet Mirror

Thanks to all. I didn't know about the Adapted Lens Talk forum on DPReview.

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Re: Lens, Meet Mirror


@MikeSowsun wrote:

I have used many different film era manual focus lenses with adapters on my Canon DSLRs, and it is only the larger mirrors of Full Frame cameras that can have a problem with hitting the mirror.  This usually happenss with shorter focal lenth lenses when the rear element moves back in order to reach infinty focus. 

 

Because the T7 is a crop camera,  I can't think of any lens combination that would interfere with the mirror.

 


Why would that even be a concern?

 

There must be something really obvious and so simple that I am overlooking it.  Let's assume that I use a reversing lens adapter.  It screws onto the filter threads.  The business end of the lens is facing forward.  It would seem to me that lens internals moving to and fro, in and out and about, would be a "don't care condition."  

 

The only part of the "macro lens" that stands a chance of getting hit by the mirror would be the front element of the now reversed lens.  Seeing how mirrors do not extend out of the body, and the front element cannot extend into the body, then I do not see what the problem could possibly be.

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"Doctor told me to get out and walk, so I bought a Canon."
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Re: Lens, Meet Mirror


@Waddizzle wrote:

@MikeSowsun wrote:

I have used many different film era manual focus lenses with adapters on my Canon DSLRs, and it is only the larger mirrors of Full Frame cameras that can have a problem with hitting the mirror.  This usually happenss with shorter focal lenth lenses when the rear element moves back in order to reach infinty focus. 

 

Because the T7 is a crop camera,  I can't think of any lens combination that would interfere with the mirror.

 


Why would that even be a concern?

 

There must be something really obvious and so simple that I am overlooking it.  Let's assume that I use a reversing lens adapter.  It screws onto the filter threads.  The business end of the lens is facing forward.  It would seem to me that lens internals moving to and fro, in and out and about, would be a "don't care condition."  

 

The only part of the "macro lens" that stands a chance of getting hit by the mirror would be the front element of the now reversed lens.  Seeing how mirrors do not extend out of the body, and the front element cannot extend into the body, then I do not see what the problem could possibly be.


Where did reversed lenses and macro come from?

John Hoffman
Conway, NH

1D X Mark III, Rebel T5i, Many lenses, Pixma PRO-100, MX472, LR Classic
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Re: Lens, Meet Mirror

"Where did reversed lenses and macro come from?"

 

Good question!  

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"Doctor told me to get out and walk, so I bought a Canon."
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Re: Lens, Meet Mirror

"...enjoy using Takumar and other M42 lenses with it."

 

I also went through this period of trying to use older lenses on my newer DSLR cameras. I ahve so darned many it is hard to see them sit. Spent a lot of time. Spent a lot of money. I can confidently say it is not worth it. I know that isn't going to deter you so by all means go ahead as it is somewhat enjoyable hobby.  But keep in mind almost any, repeat any, new designed for a DSLR will produce better images.

 

One lens I really liked and actually turned out doing a pretty nice job is my FD 500mm f8 L CAT. I would not call the photos great but they are interesting to say the least.

EOS 1DX and 1D Mk IV and several lenses!
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Re: Lens, Meet Mirror


@Waddizzle wrote:

"Where did reversed lenses and macro come from?"

 

Good question!  


Ah, wrong thread!

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"Doctor told me to get out and walk, so I bought a Canon."
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