Leica 28 v ZF25 ?
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j.liam
Registered: Dec 13, 2009
Total Posts: 2287
Country: United States

Isn't the ZF25 really 25.7mm? Assuming the Leica is in fact 28.0 mm, that doesn't result in a remarkably different FOV.



Tariq Gibran
Registered: Oct 01, 2006
Total Posts: 10846
Country: United States

j.liam wrote:
Isn't the ZF25 really 25.7mm? Assuming the Leica is in fact 28.0 mm, that doesn't result in a remarkably different FOV.


Leica lists the 28 as 28.5mm with fov of 75, 65, 46 degrees (diagonal, horizontal, vertical).

Where did you get the 25.7 spec for the Zeiss? If so, that's very interesting. On their spec sheet for the ZF2, they list it as 25mm with fov of 80, 70, 50 degrees respectively. Perhaps Zeiss is not showing the actual focal length?
Anyway, for some, they will be plenty close to interchange, for others, not close enough. I always mentally interchanged the Zeiss 25mm with the 24mm focal length but if it is indeed closer to 26mm, that's relevant since a 24mm lens often will have a diagonal fov of 84 degrees (and a difference from 84 to 75 degrees is fairly noticeable on the wide end).



Specularist
Registered: Jul 12, 2009
Total Posts: 437
Country: France

s23chang wrote:
well... if you don't plan to shoot at 2.8 to 4, ZF25 does its job from 5.6 and up.


I own the ZF Distagon 25 mm, and I would argue that for use at infinity it performs very well at large apertures. Quite possibly better than the Elmarit-R 28 mm, and certainly better than many other prime lenses I've used. Unlike the ZF Distagon 28 mm, for example, it retains fine detail right into the extreme corners at f/2.8.

The Distagon 25 mm has two main weaknesses as I use it: strong astigmatism and overall curvature of field at close focus distances (hard to avoid in a unit-focusing retrofocus lens); and moderately strong lateral chromatic aberration that limits its performance at smaller apertures.

Nice lens nevertheless, with excellent resistance to flare.



Lars Johnsson
Registered: Jun 29, 2003
Total Posts: 33650
Country: Thailand

Tariq Gibran wrote:
j.liam wrote:
Isn't the ZF25 really 25.7mm? Assuming the Leica is in fact 28.0 mm, that doesn't result in a remarkably different FOV.


Leica lists the 28 as 28.5mm with fov of 75, 65, 46 degrees (diagonal, horizontal, vertical).

Where did you get the 25.7 spec for the Zeiss? If so, that's very interesting. On their spec sheet for the ZF2, they list it as 25mm with fov of 80, 70, 50 degrees respectively. Perhaps Zeiss is not showing the actual focal length?
Anyway, for some, they will be plenty close to interchange, for others, not close enough. I always mentally interchanged the Zeiss 25mm with the 24mm focal length but if it is indeed closer to 26mm, that's relevant since a 24mm lens often will have a diagonal fov of 84 degrees (and a difference from 84 to 75 degrees is fairly noticeable on the wide end).


Lloyd Chambers write that the lens is 25,7 in his review



j.liam
Registered: Dec 13, 2009
Total Posts: 2287
Country: United States

Tariq Gibran wrote:
j.liam wrote:
Isn't the ZF25 really 25.7mm? Assuming the Leica is in fact 28.0 mm, that doesn't result in a remarkably different FOV.


Leica lists the 28 as 28.5mm with fov of 75, 65, 46 degrees (diagonal, horizontal, vertical).

Where did you get the 25.7 spec for the Zeiss? If so, that's very interesting. On their spec sheet for the ZF2, they list it as 25mm with fov of 80, 70, 50 degrees respectively. Perhaps Zeiss is not showing the actual focal length?
Anyway, for some, they will be plenty close to interchange, for others, not close enough. I always mentally interchanged the Zeiss 25mm with the 24mm focal length but if it is indeed closer to 26mm, that's relevant since a 24mm lens often will have a diagonal fov of 84 degrees (and a difference from 84 to 75 degrees is fairly noticeable on the wide end).


If you have a subscription to Lloyd Chambers' guide to Zeiss lenses, it's right up there in the first paragraph:

http://diglloyd.com/prem/prot/ZF/publish/25Distagon.html

In his review, the "cheat", as he calls it, is one of the reason he cites why someone might forego the 25 for the 28 because of its less extreme FC up close and the extra stop in comparison.



Tariq Gibran
Registered: Oct 01, 2006
Total Posts: 10846
Country: United States

j.liam wrote:
Tariq Gibran wrote:
j.liam wrote:
Isn't the ZF25 really 25.7mm? Assuming the Leica is in fact 28.0 mm, that doesn't result in a remarkably different FOV.


Leica lists the 28 as 28.5mm with fov of 75, 65, 46 degrees (diagonal, horizontal, vertical).

Where did you get the 25.7 spec for the Zeiss? If so, that's very interesting. On their spec sheet for the ZF2, they list it as 25mm with fov of 80, 70, 50 degrees respectively. Perhaps Zeiss is not showing the actual focal length?
Anyway, for some, they will be plenty close to interchange, for others, not close enough. I always mentally interchanged the Zeiss 25mm with the 24mm focal length but if it is indeed closer to 26mm, that's relevant since a 24mm lens often will have a diagonal fov of 84 degrees (and a difference from 84 to 75 degrees is fairly noticeable on the wide end).


If you have a subscription to Lloyd Chambers' guide to Zeiss lenses, it's right up there in the first paragraph:

http://diglloyd.com/prem/prot/ZF/publish/25Distagon.html

25.7mm. In his review, it's one of the reason he cites why someone might forego the 25 for the 28 because of its extreme FC up close and the extra stop.


Interesting. Curious that Zeiss would not state the actual focal length on their spec sheet like Leica does.



AhamB
Registered: Jul 11, 2008
Total Posts: 5082
Country: United States

@Tariq: The ZF25 PDF says 25.7mm, 80.2/80 degree angles.

One small advantage for the the ZF is that it has 9 aperture blades, which gives nice 18-pointed diffraction stars when shooting with the sun in the frame, or night shots with lights in them. The Leica will produce boring 6-pointed stars. When doing close-ups the Leica will also produce hexagons/lines in the bokeh when shot at anything other than wide open.



Tariq Gibran
Registered: Oct 01, 2006
Total Posts: 10846
Country: United States

AhamB wrote:
@Tariq: The ZF25 PDF says 25.7mm, 80.2/80 degree angles.

One small advantage for the the ZF is that it has 9 aperture blades, which gives nice 18-pointed diffraction stars when shooting with the sun in the frame, or night shots with lights in them. The Leica will produce boring 6-pointed stars. When doing close-ups the Leica will also produce hexagons/lines in the bokeh when shot at anything other than wide open.


So, the ZF differs from the ZF.2, at least regarding stated specifications.

http://lenses.zeiss.com/photo/en_DE/products/slr/distagont2825.usage.html



j.liam
Registered: Dec 13, 2009
Total Posts: 2287
Country: United States

No, Lloyd's review of the ZF 25 dates from 2007. The ZF and ZF.2 are optically identical.



Specularist
Registered: Jul 12, 2009
Total Posts: 437
Country: France

Tariq Gibran wrote:
So, the ZF differs from the ZF.2, at least regarding stated specifications.

http://lenses.zeiss.com/photo/en_DE/products/slr/distagont2825.usage.html


According to that site, the 21 mm has a focal length of 18 mm and weighs 470 g!

Zeiss' websites and marketing materials have been truly terrible for years. More often than not they make mistakes. They obviously don't think this affects their brand and sales, and hey, maybe it doesn't!

Leica, on the other hand, are admirably accurate and comprehensive in everything they publish. One must conclude these companies are run very differently.



AhamB
Registered: Jul 11, 2008
Total Posts: 5082
Country: United States

That new section of the website just isn't accurate and the numbers have been "massaged" to look more logical to lay persons. On top of that, the specs for the 21/2.8 show the ones for the 18/3.5.

The true technical specifactions should be correct in the data sheets that are available here: http://lenses.zeiss.com/photo/en_DE/service/download_center/current_data_sheets/current_data_sheets_slr.html



j.liam
Registered: Dec 13, 2009
Total Posts: 2287
Country: United States

In the meantime, notwithstanding their sloppiness on detail Zeiss reported record profits while Leica skirts with viability for years, foregoes the 35mm DSLR market, fixates on rangefinders fewer and fewer people buy into and dives into 20,000 medium format DSLR's. Who knows what's right...



Tariq Gibran
Registered: Oct 01, 2006
Total Posts: 10846
Country: United States

I do think Leica may be doing much better financially these days but regardless, I am surprised at the sloppiness of Zeiss in failing to post accurate specifications where the majority of folks will be looking. The average customer for high end Zeiss is not generally the average lay person and I would think their prime customer base would appreciate accuracy. It reflects poorly on a company renowned for precise optics when they show such sloppiness imho.



AhamB
Registered: Jul 11, 2008
Total Posts: 5082
Country: United States

I'm seeing more and more lay persons opening threads about which Zeiss they should buy, tbh. And Zeiss just have sloppy web designers/bad QC on the website. It would be nice though if they would just provide direct links to the data sheets instead of hiding them under service>download center>recent data sheets.



Tariq Gibran
Registered: Oct 01, 2006
Total Posts: 10846
Country: United States

AhamB wrote:
And Zeiss just have sloppy web designers/bad QC on the website. It would be nice though if they would just provide direct links to the data sheets instead of hiding them under service>download center>recent data sheets.


The odd/ worrisome thing though is that if you download the actual product flyer brochure for the lens - which looks like it is also a printed piece - Zeiss lists the same specifications as the website. So, this begs the question - will Zeiss no longer be listing accurate focal lengths for their lenses going forward in all marketing material? Will they also eventually do away with publishing MTF's (which is not listed in the product flyer for the lens by the way)? In fact, on the Zeiss lens page, I no longer even see how to get to the MTF's. Seems a slippery slope.



AhamB
Registered: Jul 11, 2008
Total Posts: 5082
Country: United States

Leica 'solved' it by not showing the tech specs, but only offering a link to the data sheet of their lenses.



Tariq Gibran
Registered: Oct 01, 2006
Total Posts: 10846
Country: United States

AhamB wrote:
Leica 'solved' it by not showing the tech specs, but only offering a link to the data sheet of their lenses.


...and by discontinuing the entire R system, thereby they no longer have to worry about the marketing.



Jason_Thames
Registered: Mar 18, 2008
Total Posts: 178
Country: United States

I must say, in all of the images you have posted, I really like the R28 images better. I bet I would like them better at 100% as well. That is high praise coming from a Zeiss-o-holic like me, but the R28 is pretty damn special. One day I will find a copy for the right price, and all of my other 28's will be hitting the road...

-Jason



philip_pj
Registered: Apr 03, 2009
Total Posts: 3106
Country: Australia

If CZ strike a high level of market success with all the Canon FF DSLR users (many of whom seem quite excited to spend up bit on white lenses, believing them to be the best thing since sliced bread), perhaps Leica will re-enter the market with their own line of warmed over 'digital quality' R lenses.

Zeiss should buy some decent space in the mainstream photographic press for something similar to denoir's comparison tests, a lot of people in more accepted fora are still ignorant of what is on offer and how easy and affordable buy in actually is, for the cheaper ZEs, at least.

This is why I say that if Zeiss ever feels like making a fabulous 24-70/2.8 AF ZE, watch them go. They should also insist on cross-platform marketing for any Sony lenses in future.

If the mags would publish such promotional material, of course.



AhamB
Registered: Jul 11, 2008
Total Posts: 5082
Country: United States

^The mags? People still read those paper things?



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