Jan Madsen

Lives in Denmark Borup, Denmark
Works as a Software development
Joined on Sep 20, 2006

Comments

Total: 25, showing: 1 – 20
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Trying hard to justify buying the new 70mm... The existing 70mm is my most used lens for macro - it is difficult to imagine better optics, as it is sharp all over at all apertures, and even the AF is precise (albeit not exactly elegant with the bzzz micro motor).

Link | Posted on Mar 4, 2018 at 09:44 UTC as 17th comment | 2 replies
In reply to:

sh10453: Max diameter 92mm. Filter size 86mm. Weight w/cap 1.3Kgm (without a filter or a polarizer).
That is one heck of a big 50mm.
I'm sticking with my Canon 50mm f/1.2 L.

Bredon1000: If your Canon 50mm f/1.2 is "very soft" wide open it is defective. Mine isn't. It is of course not stellar in the corners though.

Link | Posted on Feb 20, 2018 at 18:41 UTC
In reply to:

Nikolay Mons 2016: If this lens is going to be 'the one', indeed beating 50mpix, etc, etc, it will be the one for photographers. Not for shooters (those who need AF, lightweight, etc.). Did I mention you CANNOT get an online update of the firmware to this lens either. Because there will be no firmware. :)
One of the main difference between the photographers and shooters is the formers get comfortable only after getting an indeed very good picture (i.e. almost never, because they are rarely satisfied), but the latter MUST feel comfortably at ANY stage of shooting, no matter what is the result :) .

Wrong, it HAS firmware. The lens has an electronically controlled aperture and electronic communication with the camera, and thus needs firmware. It might not be possible to update it though.

Link | Posted on Feb 20, 2018 at 18:38 UTC

A rather ridiculous test... A 50mm lens made for 24x36mm format put onto a camera with a tiny sensor (full frame speaking). But the lens made a good show of itself, the footing looks fine. The Canon 50mm is actually a decent lens, and the Yongnuo only slightly worse (I have both myself). But mechanics are awful on both.

Link | Posted on Jan 18, 2018 at 18:26 UTC as 14th comment
On article Canon patents 400mm F5.6 catadioptric 'mirror' lens (220 comments in total)
In reply to:

Weia: The picture of the patent show that the big mirror is at the back side of the element, so light passes two times through that element. With todays computerized design and wide choice of glasses this could maybe lead to better correction than old catadioptric designs. My old Sigma 600 which I used at an Olympus OM2, turned out to be quite bad when put on a digital E3... Bokeh is horrible. But for some objects it is not important, the moon for example. I had it for its compactness, for in my backpack.

Mirroring the back surface gives you two advantages:
1) Extra freedom for the optical designer, as the glass light now goes through (twice) is an extra set of curvature/glass type parameters that can be used for correction (but introduces a little chromatic aberration). This can potentially eliminate one separate lens in the system.
2) It protects the mirror coating. With age front coated mirrors can get foggy, or develop spots in humid conditions.

Link | Posted on Dec 16, 2017 at 10:42 UTC

My old INA 135mm f/1.8 lens has 18 blades...!

Link | Posted on Sep 20, 2017 at 19:22 UTC as 63rd comment | 2 replies

There is something fundamentally wrong with your article - sorry... Interesting Minolta lens, BUT:
1) 99% of all zooms use non-linear movements of most lens groups, through cam/groove mechanics, NOT by using threaded gearing - it is simply not possible to make zoom lenses without non-linear movements, unless they are optically compensated. Even focusing is often non-linear on modern designs.
2) The Voigtländer Zoomar 36-82mm is a push/pull zoom (like many others), and there is no rotation involved in zooming with it (there is for focusing). It is optically compensated, which is relatively rare, and not used anymore. I have an example in M42 mount, it is beautifully made, but optically rather bad (as expected, it was the pioneer in 35mm format).
Please, a little more research before writing such stuff, people expect the contents to be fairly accurate.

Link | Posted on Aug 15, 2017 at 17:48 UTC as 21st comment | 3 replies
In reply to:

stratplaya: I'd like to know if the 11-24 f/4 L was an attempt to counter Nikon's 14-24 f/2.8.

Hardly - they are very different, 11mm is so much wider than 14mm, they clearly went for widest angle of view over largest aperture.

Link | Posted on Mar 22, 2017 at 18:46 UTC
On article Throwback Thursday: the Canon EF 24-70mm F2.8L (116 comments in total)

Not entirely correct, Sigma had a 24-70 f/2.8 AF in its catalog for 2001.

Link | Posted on Feb 24, 2017 at 07:12 UTC as 11th comment
On article 20:20 vision: Hands-on with Sigma's 20mm F1.4 'Art' (146 comments in total)
In reply to:

noflashplease: By all accounts, Nikon's 20mm F/1.8 is sharp wide open, takes standard 77mm filters and lens caps. Canon doesn't have anything comparable, of course.

noflashplease: Canon FD 20mm and EF 20mm lenses have completely different optical designs.

Link | Posted on Oct 23, 2015 at 08:29 UTC
In reply to:

Jan Madsen: I purchased the previous version. A good idea, but unfortunately a completely useless system. Far too many bugs, and when I eventually got a measurement / AF correction it was often way off for large aperture lenses - where it really counts. For F/2 and smaller apertures it works ok, for f/1.2 the results fluctuates, and for the Canon 50mm f/1.0 it is almost impossible to get anything meaningful out of the system.

Now if only Reikan would offer support, and correct the numerous bugs, fine, but this company has offered the worst support I have ever encountered with a commercial product - that is none. You can create a support case, and then - nothing. No answer for months. Only way to get any kind of reply from them is to plaster their Facebook wall with notes about the poor service - that worked twice, but then silence again. Unless Reikan has made a dramatic change of attitude towards the customers I would say use other options. Sadly.

I also have the 85mm f/1.2, and like Dr_Jon has experienced the rather high level of purple fringing at f/1.2. It is really annoying on high contrast subjects. Other than that (and the weight!) it is a wonderful lens, much easier to use than the 50mm f/1.

Link | Posted on Apr 3, 2015 at 08:27 UTC
In reply to:

Jan Madsen: I purchased the previous version. A good idea, but unfortunately a completely useless system. Far too many bugs, and when I eventually got a measurement / AF correction it was often way off for large aperture lenses - where it really counts. For F/2 and smaller apertures it works ok, for f/1.2 the results fluctuates, and for the Canon 50mm f/1.0 it is almost impossible to get anything meaningful out of the system.

Now if only Reikan would offer support, and correct the numerous bugs, fine, but this company has offered the worst support I have ever encountered with a commercial product - that is none. You can create a support case, and then - nothing. No answer for months. Only way to get any kind of reply from them is to plaster their Facebook wall with notes about the poor service - that worked twice, but then silence again. Unless Reikan has made a dramatic change of attitude towards the customers I would say use other options. Sadly.

Rishi: The 50mm f/1 has a lot of longitudinal chromatic abberation mixed with some spherical abberation, so when you look at a point source of light (at f/1 of course) and racks the focus manually from front focus to back focus the light goes from a green diffuse blob through a minimum of spherical abberation to a red blob, but where other lenses with less extreme aperture have a well defined best point of focus the 50mm f/1 has a more diffuse transition through best focus, so what is really the best focus is not that simple... Accepting a little spherical abberation gives highest sharpness (which is still not that good), but also rather low contrast, while minimizing spherical abberation gives better contrast, but even lower sharpness. Pick your poison... The lens is best for moody, low contrast subjects, it is certainly not the sharpness king, not even stepped well down (center gets pretty good, corners never).

Link | Posted on Apr 3, 2015 at 08:23 UTC
In reply to:

Jan Madsen: I purchased the previous version. A good idea, but unfortunately a completely useless system. Far too many bugs, and when I eventually got a measurement / AF correction it was often way off for large aperture lenses - where it really counts. For F/2 and smaller apertures it works ok, for f/1.2 the results fluctuates, and for the Canon 50mm f/1.0 it is almost impossible to get anything meaningful out of the system.

Now if only Reikan would offer support, and correct the numerous bugs, fine, but this company has offered the worst support I have ever encountered with a commercial product - that is none. You can create a support case, and then - nothing. No answer for months. Only way to get any kind of reply from them is to plaster their Facebook wall with notes about the poor service - that worked twice, but then silence again. Unless Reikan has made a dramatic change of attitude towards the customers I would say use other options. Sadly.

Rishi: Reikan software gave consistent results with the 85mm f/1.2 II on a majority of the runs, but on some runs the result would be another value, clearly off. Setup the same for all runs.

The 50mm f/1 gave results totally off on all runs, and with values all over the place. Admitted, it is a difficult lens, as maximum sharpness is a rather diffuse concept with this lens (at f/1 of course): You can try to minimize spherical abberation (one value), longitudinal chromatic abberation (another value) or some compromise in between (a third value) - and it varies with focus distance... But the Reikan software should at least give consistent results. When I finally got a reply from Reikan (after 37 days) they admitted never having tried the 50mm f/1, and suggested I use another USB cable!

Shooting real world the results are consistent, even for the 50mm f/1. I have a 1Ds-II (good AF), and a 5D-II (so-so AF) so the results are within the capabilities of the camera AF systems.

Link | Posted on Mar 27, 2015 at 08:41 UTC

I purchased the previous version. A good idea, but unfortunately a completely useless system. Far too many bugs, and when I eventually got a measurement / AF correction it was often way off for large aperture lenses - where it really counts. For F/2 and smaller apertures it works ok, for f/1.2 the results fluctuates, and for the Canon 50mm f/1.0 it is almost impossible to get anything meaningful out of the system.

Now if only Reikan would offer support, and correct the numerous bugs, fine, but this company has offered the worst support I have ever encountered with a commercial product - that is none. You can create a support case, and then - nothing. No answer for months. Only way to get any kind of reply from them is to plaster their Facebook wall with notes about the poor service - that worked twice, but then silence again. Unless Reikan has made a dramatic change of attitude towards the customers I would say use other options. Sadly.

Link | Posted on Mar 26, 2015 at 05:48 UTC as 13th comment | 9 replies
On article Go wide! Hands-on with Canon's 11-24mm F4 L (217 comments in total)
In reply to:

mrc4nl: "According to Canon, the 11-24mm's front element is the largest ever manufactured for an SLR lens, at 87mm in diameter"

Nah, the front element of the nikon 6mm f2.8 is bigger(by a wide margin) 200mm!

Nikon 1200-1700mm f/5.6-8: 212mm.
Canon 1200mm f/5.6: 214mm!

Link | Posted on Feb 8, 2015 at 10:51 UTC
On article Go wide! Hands-on with Canon's 11-24mm F4 L (217 comments in total)
In reply to:

(unknown member): Only f4? Who wants a lens that slow? I think the Nikon 14-24 f2.8 is still better.

You can't compare 11 and 14mm, there is a huge difference.

Link | Posted on Feb 7, 2015 at 22:39 UTC
On article Go wide! Hands-on with Canon's 11-24mm F4 L (217 comments in total)
In reply to:

mrc4nl: "According to Canon, the 11-24mm's front element is the largest ever manufactured for an SLR lens, at 87mm in diameter"

Nah, the front element of the nikon 6mm f2.8 is bigger(by a wide margin) 200mm!

Presumably they mean "largest aspherical lens element", otherwise it doesn't make sense. The Nikon 13mm (to stay with the rectilinear lens type) is far bigger.

Link | Posted on Feb 7, 2015 at 22:38 UTC
On article Go wide! Hands-on with Canon's 11-24mm F4 L (217 comments in total)
In reply to:

COSTISTOICA: Yesss, canon wins. canon has need 40 years to beat Nikon 13mm f/5,6 wide angle lens :
" The 13mm is Nikon's greatest lens. It is Nikon's greatest lens because not only is it big and supremely expensive, it is Nikon's, and perhaps photography's, greatest lens because it lets us make photographs we can make no other way.

The Nikon 13mm is the world's widest non-distorting professional SLR lens ever made, by anyone, in any format. It allows us to get closer to our subjects, stretch distances and create images from perspectives otherwise unimaginable. "

The Sigma 12-24mm Mk. I has very low distortion, low at 12mm, almost gone at 13mm. The Mk. II is quite different, with lots of it. Will be interesting to see the distortion level of the Canon 11-24mm.

Link | Posted on Feb 7, 2015 at 22:36 UTC
On article Canon introduces 11-24mm f/4L USM wide angle zoom (51 comments in total)
In reply to:

Peiasdf: Fancy. Is this the widest rectangular-wide production lens ever made?

I think you are mixing things up... Widest Nikon is the 13mm f/5.6 from 1975. The Nikon 12-24mm f/4 is a DX lens. Sigma 12-24mm was wide angle king in rectilinear 24x36mm lenses until today.

Link | Posted on Feb 7, 2015 at 22:13 UTC
On article Nikon AF-S Nikkor 58mm f/1.4G review (416 comments in total)
In reply to:

Scottelly: I wish they would just update the 50mm f1.2 AIS lens into an auto-focus G lens with nano-crystal coatings (to slightly improve the image quality) with the EXACT SAME optics in all other respects. That would be AWESOME. Of course, maybe they already considered that, and they decided not to mess with a good thing (they already have the 50mm f1.2 AIS, and it works great). This lens certainly gives people more choice, doesn't it?

Scottelly you need to view the rear pupil with the eye approximately where the sensor is - everything else doesn't make sense - photos of the rear pupil are from far away, and will show wildly varying sizes. Put your eye close to the rear of the lens, and the f/1.2 pupil will look nearly the same both for a 50mm and a 85mm. And yes, the Canon EF mount is substantially larger, so that f/1.2 is easy, and f/1 is just possible. Furthermore, the smaller Nikon F mount is further from the sensor (enough space for a Nikon->Canon converter ring), making things even worse.

Link | Posted on Jan 5, 2014 at 21:59 UTC
Total: 25, showing: 1 – 20
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