Help with bellows

Sandman wrote in
:

In article , Peter Irwin
wrote:

Sandman wrote:

Now, my question is what do I use a bellow for? Is it only for Macro?
I put the 35mm on it but I couldn't get it to focus on anything. The
120mm on the bellow makes for a pretty nice macro rig it seems, and
the same with the 80mm.

Why wouldn't the 35mm work?

A retrofocus (inverted telephoto) wide angle lens is designed so
that the lens is for most optical purposes rather closer to
the film plane than its physical position. Mounted directly to
the camera and set at infinity the lens is optically 35mm from
the film plane, but is physically rather farther away in order
to avoid hitting the mirror box. If you give it an additional
35mm or more outfocus with bellows or rings the lens will be optically
70mm from the film plane and will focus on a plane 70mm in front
of the optical position of the lens. It is quite likely that
this may be very close to or even inside the physical lens.

At 1:1 macro the distance from film plane to subject plane
is 4 times the focal length of the lens (plus a little bit).
If 140mm is less than the distance between the film plane
and the front of the lens when the 35mm lens is on the bellows,
that would make it impossible to achieve focus.

If you use a reversing ring and mount the lens back to front
on the bellows then the retrofocus feature of the lens will give
you a bit extra lens to subject distance while giving more
magnification for a given lens to film distance. How well the
lens will perform optically used in this way can vary quite a
bit, but it may be worth the experiment.

That being said, I think you will find the 120mm lens the most
generally useful on the bellows. Most of the time the long
lens to subject distance made possible by the long focal length
is an advantage. For 1:1 macro, the film plane and the subject plane
will be a little over 480mm distant with the 120mm lens.

Peter.

Thank you for that exhaustive reply!

So, if I'm reading you correctly, a bellow like this is only used for
Macro photography? Why then does it have tilt? I mean, tilting the focal
plane in macro seems just odd to me.

It's not odd. Macro shooting gives you very little depth of field. Tilting
lets you control the plane of the in-focus area so subject elements at
slightly different distances from the lens can be in focus.

Large format cameras usually have built in bellows, but I guess that's
not the same thing as this one?


Large format lenses do not have internal focus mechanisms like your lenses.
The bellows are their means of focussing - far or close. They don't usually
extend far enough for macro work but some allow adding an additional
bellows to get the needed length.

In article ,
Jeff wrote:

So, if I'm reading you correctly, a bellow like this is only used for
Macro photography? Why then does it have tilt? I mean, tilting the focal
plane in macro seems just odd to me.

It's not odd. Macro shooting gives you very little depth of field. Tilting
lets you control the plane of the in-focus area so subject elements at
slightly different distances from the lens can be in focus.

Yeah, that seems logical, of course.

Seems you need special lenses for infinity focus while using bellows.

Large format cameras usually have built in bellows, but I guess that's
not the same thing as this one?

Large format lenses do not have internal focus mechanisms like your lenses.
The bellows are their means of focussing - far or close. They don't usually
extend far enough for macro work but some allow adding an additional
bellows to get the needed length.

Ah, of course. It forgot about that.






--
Sandman[.net]

Sandman wrote in news:mr-DF30DB.07392020082013
@News.Individual.NET:

In article ,
PeterN wrote:

Since the bellows allows one to move the front element of the lens
closer to the subject, by increasing the distance between the rear
element and the film/sensor plane, is it possible that you either did
not get close enough, or the bellows extended too far. Just a thought.

You mean for the 35mm lens? Peter gave a pretty god reply as to why that
may be.

But I'm still wondering whether the bellow can be used for anything but
macro photography.

Looking he
http://www.flickriver.com/photos/alfiegoodrich/4695413593/

That seems to be a shot of a boy on the street using the Auto Bellows,
but it isn't Macro.

He used a "113mm back-focus Kodak Ektar 127mm f/4.7" lens, which I am
thinking may be in reference to mounting the lens backwards? Could this
be the case?


The back-focus refers to lens-to-film distance. The Ektar is a large format
(4x5) lens, designed to work at a farther from the film than your normal
Mamiya lens. Since your bellows adds some lens extension even at its
shortest length, you need a longer back-focus in order to focus to
infinity.

Mounting a lens backwards is primarily to solve field curvature issues at
macro distances, AFAIK. It does not work well with all lenses.

Sandman wrote:
In article ,
(Floyd L. Davidson) wrote:

Looking he
http://www.flickriver.com/photos/alfiegoodrich/4695413593/

That seems to be a shot of a boy on the street using the Auto Bellows,
but it isn't Macro.

He used a "113mm back-focus Kodak Ektar 127mm f/4.7" lens, which I am
thinking may be in reference to mounting the lens backwards? Could this
be the case?



I admit not knowing enough about optical science to help you. when I am
not sure of an optical effect, I have to experiment.

Yeah, I don't have a reverse adapter... yet.

Which makes no difference at all. "Back focus" has nothing to do
with a reverse adapter. It does have a lot to do with mounting a
bellows between the lens and the camera though...

Right, ok. So that means that the question remains;

It remains for you.

How to do I use the
bellows with my 120mm Sekor lens to take a portrait photo like above?
When I mount the bellows between the lens and the camera, I end up with
a Macro setup, that can only focus some centimeters in front of the
lens.

That is *of course* true. Sheesh, you can't be that
ignorant of how a lens works... can you?

Check the back focus!

But since you've mentioned so many times that you know everything
possible

Very good Floyd, when you have nothing, resort to lies. That always
works for you.

You are the one who has claimed to know virtually
everything... And it is hilarious that you, even now,
claim I have nothing while you as always start and end
with insults.

I'm having a hard time understanding why you can't even figure all
this out...

Lack of experience and knowledge! One would think that the presence of a
question would suggest that a lack of knowledge exists, right?

Well you do seem to lack a lot of knowledge, not to
mention the very small bit of intelligence it would have
taken to already have figured out the answers to such
simple minded questions.

It's easy enough, all you need to do is compare the
design target for back focus on that lens, and then
measure where the lens is physically mounted, to get an
very clear picture of how the combination you have works
or does not work.

Or to put it another way, figure out where the lens
needs to be position to allow it to focus at infinity,
or at 10 feet, or at 10 cm?

Whatever, I don't see this conversation going anywhere,
so I'll return to reading the thread for laughs.

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

In article ,
Jeff wrote:

Since the bellows allows one to move the front element of the lens
closer to the subject, by increasing the distance between the rear
element and the film/sensor plane, is it possible that you either did
not get close enough, or the bellows extended too far. Just a thought.

You mean for the 35mm lens? Peter gave a pretty god reply as to why that
may be.

But I'm still wondering whether the bellow can be used for anything but
macro photography.

Looking he
http://www.flickriver.com/photos/alfiegoodrich/4695413593/

That seems to be a shot of a boy on the street using the Auto Bellows,
but it isn't Macro.

He used a "113mm back-focus Kodak Ektar 127mm f/4.7" lens, which I am
thinking may be in reference to mounting the lens backwards? Could this
be the case?


The back-focus refers to lens-to-film distance. The Ektar is a large format
(4x5) lens, designed to work at a farther from the film than your normal
Mamiya lens. Since your bellows adds some lens extension even at its
shortest length, you need a longer back-focus in order to focus to
infinity.

Mounting a lens backwards is primarily to solve field curvature issues at
macro distances, AFAIK. It does not work well with all lenses.

Right, thanks for the explanation!


--
Sandman[.net]

In article ,
(Floyd L. Davidson) wrote:

Which makes no difference at all. "Back focus" has nothing to do
with a reverse adapter. It does have a lot to do with mounting a
bellows between the lens and the camera though...

Right, ok. So that means that the question remains;

It remains for you.

No ****, Sherlock? How did you figure THAT out? You're some genius!

How to do I use the bellows with my 120mm Sekor lens to take a
portrait photo like above? When I mount the bellows between the lens
and the camera, I end up with a Macro setup, that can only focus
some centimeters in front of the lens.

That is *of course* true. Sheesh, you can't be that
ignorant of how a lens works... can you?

I thought we had already established that I am that ignorant on how
bellows works. It was written in plain English Floyd, so no wonder you
missed it, ey?

But since you've mentioned so many times that you know everything
possible

Very good Floyd, when you have nothing, resort to lies. That always
works for you.

You are the one who has claimed to know virtually
everything...

Keep them lies coming Floyd. It's all you got. In fact, I'll give you
one million dollars if you can quote me claiming that. One million!

And it is hilarious that you, even now, claim I have nothing while
you as always start and end with insults.

Haha, you lie about me and *I* start with insults? Not even you are this
dense, Floyd. Not even you.

I'm having a hard time understanding why you can't even figure all
this out...

Lack of experience and knowledge! One would think that the presence of a
question would suggest that a lack of knowledge exists, right?

Well you do seem to lack a lot of knowledge

No doubt! You seem surprised that there are people in the world that
lacks knowledge about bellows for cameras. :-D

not to mention the very small bit of intelligence it would have taken
to already have figured out the answers to such simple minded
questions.

A question you have failed to actually answer, showing that it is way to
big for you at least

It's easy enough, all you need to do is compare the design target for
back focus on that lens

What lens? You specifically said "that", not "your" here. So you must be
in reference to a specific lens.

and then measure where the lens is physically mounted

Compared to what? Do you mean measure the distance from the lens to the
film plane?

to get an very clear picture of how the combination you have works or
does not work.

Whether or not my combination works or not as already been established,
Floyd. Haven't you been reading anything?

Or to put it another way, figure out where the lens needs to be
position to allow it to focus at infinity, or at 10 feet, or at 10
cm?

Typical Floyd circular argument. "How do I figure out this?" - "You
figure it out".

Whatever, I don't see this conversation going anywhere,
so I'll return to reading the thread for laughs.

Haha, as if a "conversation" with you ever went anywhere. I've gotten
some really good answer from knowledgable people already. It's not like
I expected to find any in a post from you Floyd.



--
Sandman[.net]

Eric Stevens wrote:
On Mon, 19 Aug 2013 19:54:20 +0200, Sandman wrote:

--- snip ---

Sorry about all the questions. I'm a total newbie when it comes to
both analog cameras and these kind of accessories. Extender rings
aren't analog only, of course, but as far as I know, there aren't
any bellows that people normally use for Nikon/Canon cameras.

On the contrary, both Nikon and Canon (and other manufacturers) made a
variety of bellows for their 35mm cameras.

Here's a more modern way to do it:

http://www.cambo.com/Html/products_p.../Group735.html

Using something like a Schenider Digitar lens allows you to get
infinity focus.

Andrew.