PDA

View Full Version : Why 55mm f/4.5 Apo-Grandagon *and* 55mm f/4.5 Grandagon-N?



Steve Goldstein
27-Jul-2018, 14:57
These two lenses seem very similar to my unpracticed-with-wide-angles eyes. The Grandagon-N image circle is 7mm larger and its flange focal length is a 2.4mm longer. It also weighs less and takes smaller filters than the Apo-Grandagon. Any idea why Rodenstock would produce two such similar lenses? Was it a case of market segmentation and positioning like with the Apo-Sironar-N and -S?

Dan Fromm
27-Jul-2018, 15:12
55 mm Grandagon-N? Don't you mean 65 mm?

Bob Salomon
27-Jul-2018, 15:30
Same lens, Rodenstock changed the diameter to 67mm shortly after the initial production. Both are Apo Grandagon. There was an older 58mm Grandagon but no 55mm Grandagon N.

Steve Goldstein
27-Jul-2018, 16:04
55 mm Grandagon-N? Don't you mean 65 mm?

I saw this quoted on another web site, with similar but not identical specs to the Apo-Grandagon 55mm. My admittedly limited collection of Rodenstock literature agrees with what Bob said. But since it was out there somewhere I thought I'd ask, I apparently have too much time on my hands ;)

schafphoto
27-Jul-2018, 20:15
I'm very happy with my APO Grandson 55mm f4.5. Covers 4x5 with 5-7mm of shift ability, but when you need wide, it's wide. I keep getting the camera rail in the bottom of the vertical frame because I use it so seldomly, and I forget that I need to push the front and rear standards out to the front.
-Schaf

Bernice Loui
27-Jul-2018, 20:50
Notable difference between the APO Grandagon -vs- Grandagon N, MC and ... The APO Grandagon series is published to be optimized at f8-f11, While the Grandagon N, MC and ... is noted to be optimized at f22. This appears to be the published difference between the two series of Grandagon.

Regardless, the 55mm APO Grandagon is a GOOD lens, use it on 6x9 as a wide angle.


Bernice

Bob Salomon
28-Jul-2018, 06:04
Notable difference between the APO Grandagon -vs- Grandagon N, MC and ... The APO Grandagon series is published to be optimized at f8-f11, While the Grandagon N, MC and ... is noted to be optimized at f22. This appears to be the published difference between the two series of Grandagon.

Regardless, the 55mm APO Grandagon is a GOOD lens, use it on 6x9 as a wide angle.


Bernice
The difference is quite major, the Apo Grandagon are only made in 35, 45 and 55mm. The Grandagon N and the older Grandagon were made in 65 mm up except for a very old Grandagon 58mm.

Bernice Loui
28-Jul-2018, 10:20
Turns out the APO Grandagon is one of the very few production wide angles of this design to be optimized for larger apertures (f8-f11). This sets them apart from Grandagon N, Fujinon SW and SWD, Super Angulon, Nikkor SW and the rest.

Alterative would be the Zeiss Biogon and the Schneider 53mm f4 Super Angulon that was intended to be an alternative to the 53mm Biogon.


Bernice



The difference is quite major, the Apo Grandagon are only made in 35, 45 and 55mm. The Grandagon N and the older Grandagon were made in 65 mm up except for a very old Grandagon 58mm.

Dan Fromm
28-Jul-2018, 12:08
Bernice, f/4.5 Biogons cover 90 mm. The 38 covers 6x6 per Zeiss, 84 mm with good sharpness per me. The very scarce 45 covers 6x7. And the 53 covers 2x3, as does the 53/4.5 SA.

The roughly equivalent SA XLs have less coverage than Apo Grandagons. If you need what an Apo Grandy does, there are no substitutes.

Bernice Loui
29-Jul-2018, 08:43
Indeed, Trade offs are a given.

Biogons made for aerial recon were intended to be used at full aperture (Mil versions had no adjustable iris) fixed on a camera. Some decades ago there were a number of these on the US military surplus market made by Pacific Optical, Viewlex, Goerz, Zeiss. The Zeiss ones became sought after by the market due to brand identity. They were all made to a Mil spec.

The Biogon_ish wide angles for LF are designed to a different set of requirements and produce a different result. They have a larger image circle than the Biogon, intended to be used at smaller apertures, less weight, less bulk, in shutter and etc...

Not one of those who obsess over image circle as the image circle needed is simply matched to the lens required to get the image done. It does appear there is an obsession over image circle in recent years among LF folks. Wonder if this is due to the increased interest in 8x10 and larger sheet film for alternative process prints.


:)
Bernice





Bernice, f/4.5 Biogons cover 90 mm. The 38 covers 6x6 per Zeiss, 84 mm with good sharpness per me. The very scarce 45 covers 6x7. And the 53 covers 2x3, as does the 53/4.5 SA.

The roughly equivalent SA XLs have less coverage than Apo Grandagons. If you need what an Apo Grandy does, there are no substitutes.

Corran
30-Jul-2018, 10:28
The roughly equivalent SA XLs have less coverage than Apo Grandagons. If you need what an Apo Grandy does, there are no substitutes.

Dan,

I saw this and was confused. So I looked it up. Rodenstock says 163mm at f/11 for the APO Grandagon. Schneider claims 166mm for the 58mm XL, but at f/22. However, this table here (http://www.prograf.ru/rodenstock/largeformat_en.html#table1) does show a 55mm Grandagon-N with 170mm coverage. What gives? Is this 170mm coverage accurate for the APO lens, just stopped down to f/22? Or is this a typo and they meant 65mm - there is not a 65mm on the list otherwise. Perhaps this has given rise to the confusion shown by the OP?

I only have one modern Rodenstock lens so don't really pay attention to them or know much, but I always thought the Schneider XL lenses were the ones with the larger image circles, when comparing the similar lenses such as 45 / 47 and 55 / 58.

Corran
30-Jul-2018, 10:51
In fact, now that I look further down the page, the next section on image circles and shift limits shows 65mm Grandagon-N instead. So it's definitely a typo on the part of Rodenstock on their official page.

So it seems the Schneider XL lenses have more coverage, on paper anyway. How about in practice?

Here is the corrected data sheet in image form:

http://www.garrisaudiovisual.com/photosharing/rodenstock large format lens data sheet.jpg

Dan Fromm
30-Jul-2018, 11:02
Bryan, thanks for calling me on this and making me check my lookups. I must have glanced at Schneider's full aperture columns.

@f/11, the 35 Apo Grandy covers 120 degrees, 125 mm. The 45 and 55 cover 110 degrees, 131 and 163 mm respectively. All this per Rodenstock's propaganda. Since R'stock says nothing about coverage at smaller stops, I suspect that they reach full coverage at f/11.

Schneider says that the 38 and 47 SAXLs cover 120 degrees at f/22, 139 and 166 mm respectively. The 58 covers 110 degrees, 166 mm.

We can quibble about a couple of mm of focal length and how far to stop down to get full coverage, but basically I was mistaken.

Corran
30-Jul-2018, 11:05
I wonder why only the 35mm is rated at 120 degrees. If they simply increased the size of that same design to 45mm, it should cover 4x5, as does the 47mm XL.

The Rodenstock 35mm seems like a great lens and I have thought about trying to find one - the Schneider 38mm is not the sharpest lens in the world, or at least mine isn't.

Jac@stafford.net
30-Jul-2018, 15:06
[...] The Rodenstock 35mm seems like a great lens and I have thought about trying to find one [...]

Perhaps I can save you the trouble. Yes, the Rodenstock 35mm apo grandagon is very wide! I Have one on a Horseman 6x12. Two things - it is not sharp until ƒ/16 or ƒ22, and those are coincidentally the apertures required with Rodenstock's center filter. That fact makes the lens require a tripod.

Oh, with Horseman's purpose-built ground glass the image is practically impossible to see. If you use Horseman's optical viewfinder be very careful to align the mask properly.

Corran
30-Jul-2018, 15:08
Thanks Jac. Sounds about like the 38mm XL.

Bob Salomon
30-Jul-2018, 15:12
Perhaps I can save you the trouble. Yes, the Rodenstock 35mm apo grandagon is very wide! I Have one on a Horseman 6x12. Two things - it is not sharp until /16 or 22, and those are coincidentally the apertures required with Rodenstock's center filter. That fact makes the lens require a tripod.

Oh, even with Horseman's purpose-built ground glass the image is practically impossible to see. If you use Horseman's optical viewfinder be very careful to align the mask carefully.

The center filter requires stopping down 2 stops, or more. With a 4.5 lens that wouldnt be 16 or 22. Did you buy a new or used lens? Have you told Rodenstock that you think that you have a problem with it?

Are you using the proper center filter?

Jac@stafford.net
30-Jul-2018, 15:18
The center filter requires stopping down 2 stops, or more. With a 4.5 lens that wouldn’t be 16 or 22. Did you buy a new or used lens?

Is that not exactly what I wrote? I got the lens & camera brand new.


Have you told Rodenstock that you think that you have a problem with it?

Are you using the proper center filter?

Why should I talk to Rodenstock about the lens well known performance? There is no problem. It performs to published specs.

Yeah, I have the correct center filter.

What is the motivation for your post? Really.

Bob Salomon
30-Jul-2018, 16:49
Is that not exactly what I wrote? I got the lens & camera brand new.



Why should I talk to Rodenstock about the lens well known performance? There is no problem. It performs to published specs.

Yeah, I have the correct center filter.

What is the motivation for your post? Really.

No, it is not performing to spec, there is either a problem with the lens or the camera. At your noted f stops you are in diffraction.

Dan Fromm
30-Jul-2018, 17:20
Jac, R'stock documentation for Apo Grandagons says they should be used at f/8 without movements and at f/11 with. But


the required depth of field may make further stopping down necessary. In such cases, the sharpness may be reduced due to diffraction - particularly inthe center of the image circle

In other words, you make your decisions as a photographer and accept the consequences.

All this is explained in the R'stock documentation that Bob lent me and I scanned and made available on line. There's a link to it in the list.

Stopping down two stops when using a center filter is necessary to eliminate mechanical vignetting. Center filters correct only optical vignetting, the natural decline in illumination off-axis. They can do nothing about mechanical vignetting.

Jac@stafford.net
30-Jul-2018, 18:41
Dan, is that not what I wrote? There is some kind of crazy going on here.

... and the misquote is not appreciated.

Dan Fromm
30-Jul-2018, 19:00
Dan, is that not what I wrote? There is some kind of crazy going on here.

... and the misquote is not appreciated.

I didn't quote you at all. And you've forgotten what you wrote:


Two things - it is not sharp until ƒ/16 or ƒ22, and those are coincidentally the apertures required with Rodenstock's center filter.

Two stops down from f/4.5 is f/9.