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Tamron SP f5.6 / 350mm (06B) mirror lens
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PostPosted: Thu Feb 07, 2019 6:15 am    Post subject: Reply with quote

e6filmuser wrote:
... Blowing up the images to the same size as one from a full frame sensor spreads the light out further, effectively, a smaller aperture from the point of view of exposure...


You meant "from the point of view of dof" not exposure. Smile


PostPosted: Thu Feb 07, 2019 6:39 am    Post subject: Reply with quote

visualopsins wrote:
e6filmuser wrote:
... Blowing up the images to the same size as one from a full frame sensor spreads the light out further, effectively, a smaller aperture from the point of view of exposure...


You meant "from the point of view of dof" not exposure. Smile


This was wrong. I meant DOF. The spreading of light to effect exposure is relevant to extensions, magnifications and TCs and is not about sensor size.


PostPosted: Thu Feb 07, 2019 9:13 am    Post subject: Reply with quote

e6filmuser wrote:
visualopsins wrote:
e6filmuser wrote:
... Blowing up the images to the same size as one from a full frame sensor spreads the light out further, effectively, a smaller aperture from the point of view of exposure...


You meant "from the point of view of dof" not exposure. Smile


This was wrong. I meant DOF. The spreading of light to effect exposure is relevant to extensions, magnifications and TCs and is not about sensor size.


Correct!


PostPosted: Thu Feb 07, 2019 8:19 pm    Post subject: Reply with quote

I have two of these lenses and willing to sell one, if somebody is interested.


PostPosted: Fri Feb 08, 2019 5:43 pm    Post subject: Reply with quote

Lucse wrote:
I have two of these lenses and willing to sell one, if somebody is interested.


Have you tried reversing one on the other for macro? Laugh 1


PostPosted: Fri Feb 08, 2019 9:40 pm    Post subject: Reply with quote

e6filmuser wrote:
Lucse wrote:
I have two of these lenses and willing to sell one, if somebody is interested.


Have you tried reversing one on the other for macro? Laugh 1


... I am (probably) too stupid to get the joke...


PostPosted: Sun Feb 10, 2019 10:17 am    Post subject: Reply with quote

Lucse wrote:
e6filmuser wrote:
Lucse wrote:
I have two of these lenses and willing to sell one, if somebody is interested.


Have you tried reversing one on the other for macro? Laugh 1


... I am (probably) too stupid to get the joke...


Not a serious proposition.

One technique is to reverse a lens onto the front of another mounted normally on the camera. The combined diopters and short focusing distance can give good results. It is far more likely that two 50mm lenses would be used than two 350mm. However, maybe nobody has been in your unique position of owning two.


PostPosted: Sun Feb 10, 2019 5:29 pm    Post subject: Reply with quote

e6filmuser wrote:
Lucse wrote:
e6filmuser wrote:
Lucse wrote:
I have two of these lenses and willing to sell one, if somebody is interested.


Have you tried reversing one on the other for macro? Laugh 1


... I am (probably) too stupid to get the joke...


Not a serious proposition.

One technique is to reverse a lens onto the front of another mounted normally on the camera. The combined diopters and short focusing distance can give good results. It is far more likely that two 50mm lenses would be used than two 350mm. However, maybe nobody has been in your unique position of owning two.


I've got two Tamron 500mm f/8 (catadioptric) lenses as well. That would look even more impressive (and stupid, I guess) to use them as 'twin-lens-reverse'-macro set-up.
Although I seriously doubt if it's possible to use catadioptric lenses this way.
But if somebody has a 82mm coupling ring laying around I am willing to give it a try (and no, I am not willing to duck-tape them together Wink).

If it would work I would get a 500mm macro lens that gives a 1:1 magnification. (The main lens mm divided by the reversed lens mm gives the stacked lens magnification).
And that would be very hard to work with I reckon.

This makes me think: does anybody know what the focal-lenght of the longest 'normal' macro-lens is? (200mm according to me, but is that so?)


PostPosted: Mon Feb 11, 2019 8:46 am    Post subject: Reply with quote

Lucse wrote:
e6filmuser wrote:
Lucse wrote:
e6filmuser wrote:
Lucse wrote:
I have two of these lenses and willing to sell one, if somebody is interested.


Have you tried reversing one on the other for macro? Laugh 1


... I am (probably) too stupid to get the joke...


Not a serious proposition.

One technique is to reverse a lens onto the front of another mounted normally on the camera. The combined diopters and short focusing distance can give good results. It is far more likely that two 50mm lenses would be used than two 350mm. However, maybe nobody has been in your unique position of owning two.


I've got two Tamron 500mm f/8 (catadioptric) lenses as well. That would look even more impressive (and stupid, I guess) to use them as 'twin-lens-reverse'-macro set-up.
Although I seriously doubt if it's possible to use catadioptric lenses this way.
But if somebody has a 82mm coupling ring laying around I am willing to give it a try (and no, I am not willing to duck-tape them together Wink).

If it would work I would get a 500mm macro lens that gives a 1:1 magnification. (The main lens mm divided by the reversed lens mm gives the stacked lens magnification).
And that would be very hard to work with I reckon.

This makes me think: does anybody know what the focal-lenght of the longest 'normal' macro-lens is? (200mm according to me, but is that so?)


Well, that setup would make about the slowest macro lens ever made... Twisted Evil

I have a 800mm Long Distance Microscope, not really "normal" for the normal guy in the streets, but for me it is Wink


PostPosted: Mon Feb 11, 2019 9:25 am    Post subject: Reply with quote

Lucse wrote:

This makes me think: does anybody know what the focal-lenght of the longest 'normal' macro-lens is? (200mm according to me, but is that so?)


The Olympus 4/3 70-300mm ED does 1:2 at 300mm.


PostPosted: Mon Feb 11, 2019 6:24 pm    Post subject: Reply with quote

kds315* wrote:
I have a 800mm Long Distance Microscope, not really "normal" for the normal guy in the streets, but for me it is Wink


I am not that much into macro-photography. So I had never heard of Long Distance Microscopes.

But I must say; a whole new world opens up for me Smile.

e6filmuser wrote:


The Olympus 4/3 70-300mm ED does 1:2 at 300mm.


OK, not bad...but did you have a look at those Long Distance Microscopes? Wink


PostPosted: Mon Feb 11, 2019 6:41 pm    Post subject: Reply with quote

Lucse wrote:


OK, not bad...but did you have a look at those Long Distance Microscopes? Wink


With DOF of around 0.05mm, I wouldn't have a use. I have avoided looking up the prices as I have a blood pressure problem Very Happy


PostPosted: Mon Feb 11, 2019 7:11 pm    Post subject: Reply with quote

e6filmuser wrote:


With DOF of around 0.05mm, I wouldn't have a use. I have avoided looking up the prices as I have a blood pressure problem Very Happy


OK, that blood pressure problem is not good news. Does it make you cough as well?

If so, you can cough up some more money to buy an (electronic controlled) automated motorized focus stacking macro rail.

That solves the 0,05 DOF-problem Wink .


PostPosted: Mon Feb 11, 2019 7:40 pm    Post subject: Reply with quote

Lucse wrote:
e6filmuser wrote:


With DOF of around 0.05mm, I wouldn't have a use. I have avoided looking up the prices as I have a blood pressure problem Very Happy


OK, that blood pressure problem is not good news. Does it make you cough as well?

If so, you can cough up some more money to buy an (electronic controlled) automated motorized focus stacking macro rail.

That solves the 0,05 DOF-problem Wink .


I do my macro hand-held. I would need some bionics first! Smile


PostPosted: Mon Feb 11, 2019 7:40 pm    Post subject: Reply with quote

Guys, your veering off massively here. This is a thread about the Tamron SP 350mm mirror lens. Stay with that please!

I'm about to cut all this unrelated discussion off and place in in a seperate thread named, well not sure yet.. Twisted Evil

And btw e6filmuser, macro starts per definition at 1:1 (1x), you talk about "close-up" ....


PostPosted: Mon Feb 11, 2019 8:22 pm    Post subject: Reply with quote

Off topic & cross posting enrich rather than detract from a discussion imho.


PostPosted: Mon Feb 11, 2019 8:28 pm    Post subject: Reply with quote

kds315* wrote:
Guys, your veering off massively here. This is a thread about the Tamron SP 350mm mirror lens. Stay with that please!

I'm about to cut all this unrelated discussion off and place in in a seperate thread named, well not sure yet.. Twisted Evil

And btw e6filmuser, macro starts per definition at 1:1 (1x), you talk about "close-up" ....


The last sentence appears to contradict the request of the first.

By whose definition is macro 1:1? References please!


PostPosted: Mon Feb 11, 2019 9:04 pm    Post subject: Reply with quote

kds315* wrote:
Guys, your veering off massively here. This is a thread about the Tamron SP 350mm mirror lens. Stay with that please!

I'm about to cut all this unrelated discussion off and place in in a seperate thread named, well not sure yet.. Twisted Evil

And btw e6filmuser, macro starts per definition at 1:1 (1x), you talk about "close-up" ....


Not in the macro forums I subscribe to. Not that it matters. It's arbitrary.


PostPosted: Mon Feb 11, 2019 10:02 pm    Post subject: Reply with quote

kds315* wrote:
Guys, your veering off massively here. This is a thread about the Tamron SP 350mm mirror lens. Stay with that please!

I'm about to cut all this unrelated discussion off and place in in a seperate thread named, well not sure yet.. Twisted Evil

And btw e6filmuser, macro starts per definition at 1:1 (1x), you talk about "close-up" ....


Well, you could start with erasing your:
Quote:
(Oh look at me) I have a 800mm Long Distance Microscope, not really "normal" for the normal guy in the streets, but for me it is.


... and this in the MeToo times. Rolling Eyes
Laugh 1


PostPosted: Thu Feb 14, 2019 2:48 pm    Post subject: Reply with quote

Only slightly off-topic:

I just discovered that deep in my closet I have a third copy of these Tamron 350 f/5.6 lenses laying around.


Might this be some indication that I have lens lust ?


PostPosted: Sat Feb 16, 2019 12:03 pm    Post subject: Reply with quote

Two shots with the lens on m4/3. The first at a distance of ca 150 feet, the second at closer to 15 feet. The first was with my back to the sun, the second with it to my left. The images are uncropped.