WillemB

WillemB

Lives in Netherlands Netherlands
Works as a retired engineer & teacher
Joined on Nov 24, 2005
About me:

Born in '34, walk now where I used to run...

Comments

Total: 13, showing: 1 – 13
On article Pinhole Pro DSLR lens is on Kickstarter (41 comments in total)
In reply to:

makofoto: Ordered mine. I use to make my own. Drill a hole in a body cap, glue hammered brass foil over it ... it's important that the edge of the hole be super thin ... paint black and drill a tiny hole. I had a set of tiny model maker drill bits. One could even make multiple apertures to bet a Multi image prism effects.

I used to drill a small hole in thin Al-foil (from chocolate) with a (rotating) sewing needle clamped in the table drill. The Al foil was temporarily glued on a cork and afterwards glued over a hole in a body cap. I am still looking for the optimal hole diameter for a given focus length in relation to diffraction unsharpness....

Link | Posted on Nov 7, 2017 at 11:18 UTC
In reply to:

Ebrahim Saadawi: -Mirror box/shutter lag
-Inaccurate testing method: not 100% identical
1- Camera Settings
2- Subject motion
-Higher power of the Grip might push AF speed of 1 is the problem.
-Higher pixel count shows more AF inaccuracies

My head can't think of anything else!

For 100% accurate AF testing one would need some kind of automated motion subject and shooting with a fixed camera on a tripod with an external remote, using the same AF settings, burst rate, and resolution (20mp on the d850 and 7fps on the D5)

Inaccurate flange shimming!

Link | Posted on Sep 29, 2017 at 20:49 UTC

It will be unprecedented if the thumb rest is also a handle to actuate a small power generator(dynamo). One stroke for 5 shots...

Link | Posted on Sep 25, 2017 at 20:07 UTC as 14th comment | 1 reply
In reply to:

steelhead3: This could be Nikon's last gasp to stay in business.

ASML started as a split off from Philips, taking many Philips engineers with it, and stayed in the Eindhoven regio. Sony and Philips had a dispute about licenses at the time, which was being negotiated in Japan. When the Sony delegation thought they mastered the situation, they left the conference room, a heavy insult to the Dutch. The next day they came back, humbled and in tears...They had found out that they had overlooked some crucial Philips patent that could not be circumvented. Some ASML people may remember that story...

Link | Posted on May 3, 2017 at 12:56 UTC

Great documentary! Love that man Klein!

Link | Posted on May 1, 2013 at 20:54 UTC as 30th comment
On article Eurostar makes a tablet for the ladies (14 comments in total)

I guess that selling starts on April 1st!

Link | Posted on Feb 19, 2013 at 11:10 UTC as 3rd comment
On article A sneak peek at our forthcoming camera test scene (320 comments in total)
In reply to:

Mssimo: We are going to be looking at this for the next 10 years or so..i think we need to think ahead and add at least one more hot girl.

By doing some shifting there will be ample space for a beautyful doll wearing well detailled feathers on some critical spaces. Otherwise a skin detail with finely molded shadows...

Link | Posted on Oct 10, 2012 at 08:41 UTC
On article Photokina 2012: Fujifilm Stand Report (26 comments in total)
In reply to:

Nishi Drew: What XF1 color did dpreview vote on?

If there are 5 choices I will vote 2, 4,6,14, 16 so the ladies may have a bright coloured one...

Link | Posted on Sep 20, 2012 at 11:13 UTC
In reply to:

cpkuntz: Why do they use 2 mp sensors? Robust build? The Apollo mission used Hasselblads. Why not get some medium format goodness on board one of these rovers?

Because of the extreme low S/N, data transmission will be very slow; the receiver bandwidth on earth might easily be less than one Hertz...

Link | Posted on Aug 8, 2012 at 10:01 UTC
In reply to:

IcyVeins: Just wondering but why would you need f/2.8 for doing macro? Don't you usually want as much DOf as possible since you are focusing so close?

@ J.S.Wisniewski:
Thank you for pointing out the welcome effect of shrinking focus length when close focussing..I used the old formula: 1/V + 1/B = 1/F when I read that the closest focus distance was 470 mm (= distance between V and B).

'Who is John Galt'

Link | Posted on Jul 13, 2012 at 21:31 UTC
In reply to:

IcyVeins: Just wondering but why would you need f/2.8 for doing macro? Don't you usually want as much DOf as possible since you are focusing so close?

Sadly, at close-up, the effective focus length of this lens has shrunk to 117 mm when 1:1. Is this called super-focus-breathing?

Link | Posted on Jul 13, 2012 at 09:56 UTC
In reply to:

viking79: I like how it out performs all the best L glass at 40 mm, of course you give up the added range. Looks like a winner for $200.

The fact that its resolving power does not get much better by stopping down points to some residual astigmatism. Typical for a Tessar-type.

Link | Posted on Jun 22, 2012 at 09:46 UTC
Total: 13, showing: 1 – 13