135mm VS 150mm Apo Sironar S

[seandavid]

Hi all,

I have a 135mm Rodenstock Apo Sironar S. I love it. One thing I seem to run into is a slight lack of coverage in some situations.

I have an opportunity to grab a 150mm Apo Sironar S at a decent price, but I'm wondering if it's worth it (coverage-wise) for such a similar focal length?

Is sharpness a wash between the two?

Would love to hear from anyone that has experience with these lenses.

Thanks!

[Pfsor]

Hi all,

I have a 135mm Rodenstock Apo Sironar S. I love it. One thing I seem to run into is a slight lack of coverage in some situations.

I have an opportunity to grab a 150mm Apo Sironar S at a decent price, but I'm wondering if it's worth it (coverage-wise) for such a similar focal length?

Thanks!

To see if coverage-wise it is worth it simply compare the coverage specifications and there lays your answer.

[Leigh]

I have a 135mm Rodenstock Apo Sironar S. I love it. One thing I seem to run into is a slight lack of coverage in some situations.
I have an opportunity to grab a 150mm Apo Sironar S at a decent price, but I'm wondering if it's worth it (coverage-wise) for such a similar focal length?

I have both extremely good lenses. They're very similar. The designs are identical.

The image circle on the 150 is 231mm, enough to cover 5x7 with some movements.
The image circle on the 135 is 208mm, significantly less and not enough for 5x7.

Both will provide substantial movements on 4x5 with its much smaller 163mm diagonal.

You need to describe "lack of coverage" in significantly more detail.

-Leigh

[EdSawyer]

Both great lenses, no doubt. Hard to go wrong with either, they are still in demand, and anything under $700 is a good price for the 150.

[Pere Casals]

I have a 135mm Rodenstock Apo Sironar S. I love it. One thing I seem to run into is a slight lack of coverage in some situations.

If you mostly do portraits you are to prefer the 150, if you do more landscape you are to prefer the 135, probably.

IMHO it's not about coverage, it's about what you plan to mostly do with normal focal.


Also if you have a 135 next step is 180. If you have the 150 next step is the 210.

You also have a 210, so you can get the 150 and sell 135, or sell the 210 and get a 180, to have 135+180, or 150+210, in order to have a lens kit with suitable jumps of some +30%.

[seandavid]

To see if coverage-wise it is worth it simply compare the coverage specifications and there lays your answer.

Sorry, I'm still pretty green in the world of large format photography. I see the difference in specs, I just don't know how that applies to real world experience.

[seandavid]

I have both extremely good lenses. They're very similar. The designs are identical.

The image circle on the 150 is 231mm, enough to cover 5x7 with some movements.
The image circle on the 135 is 208mm, significantly less and not enough for 5x7.

Both will provide substantial movements on 4x5 with its much smaller 163mm diagonal.

You need to describe "lack of coverage" in significantly more detail.

-Leigh

Thanks for your reply, Leigh.

My experience with coverage comes from a certain subject I was shooting (An abandoned house). I wanted to create some out of focus areas in the corners, but ran out of room with the 135 which created some vignetting. I know with a lot of subjects, movements are fairly minimal. I just want the option to really experiment, as like I said, I'm pretty new to this.

Question, I would imagine not, but do you notice a difference in sharpness between the two? Or any difference in rendering of OOF (bokeh) if you ever happen to shoot close to wide open?

[seandavid]

If you mostly do portraits you are to prefer the 150, if you do more landscape you are to prefer the 135, probably.

IMHO it's not about coverage, it's about what you plan to mostly do with normal focal.


Also if you have a 135 next step is 180. If you have the 150 next step is the 210.

You also have a 210, so you can get the 150 and sell 135, or sell the 210 and get a 180, to have 135+180, or 150+210, in order to have a lens kit with suitable jumps of some +30%.

Thanks for the advice, Pere.

[Leigh]

Question, I would imagine not, but do you notice a difference in sharpness between the two? Or any difference in rendering of OOF (bokeh) if you ever happen to shoot close to wide open?

No difference in sharpness. They're the same lens.

A brief primer on lens design...

The initial specs for a lens design are aperture and coverage angle.
The reference design is then completed for a specific focal length.
Once that design is finished, other focal lengths are made by just multiplying all the dimensions by a common factor.

Simplistically, if your reference design is 100mm and you want 150mm, you multiply all the dimensions by 1.5.

That's why you frequently see the aperture first when viewing a lens name, like Distagon 8/100 meaning f/8 100mm.
Distagon f/8 is the generic design. 100mm is a specific version of that design.

It follows that the APO-Sironar-S 5.6/135mm and 5.6/150mm lenses are the same since they have the same aperture.
-----
The area that a lens can illuminate* is called the Image Circle.

You can envision this as a cone with the apex being at the rear node of the lens.
The base of the cone is the film plane. The height of the cone is the lens' focal length.

When focused at infinity, the lens' rear node is in front of the film by a distance equal to the lens focal length.
In fact, that's the definition of lens focal length.

To focus on closer subjects the lens must move away from the film.
Using the cone analogy, you can see that as the cone's height increases, its base diameter increases.
So the image circle of any lens increases as the subject gets closer.
-----
As to bokeh... that's not an attribute I pay any attention to.

- Leigh

*Yes, guys, I know the circle of illumination is larger than the circle of good definition and image quality.
This is a simplified discussion.

[Pere Casals]

*Yes, guys, I know the circle of illumination is larger than the circle of good definition and image quality.
This is a simplified discussion.

Not a simplistic discussion, but very well summarized, it clarified me some things...