http://gabriel.mp3-tech.org/blog/index.php Copyright 2010, Gabriel Bouvigne Gabriel Bouvigne en-US SPHPBLOG 0.4.8 http://gabriel.mp3-tech.org/blog/index.php?entry=entry100127-135749
I decided to copy this one:



It is from the Corbis library (copyright Riou/photocuisine/Corbis).

First shot with most of the set-up done, natural light from a window on the right:


Set white balance manually using the plate:


Add the chocolate. I did not put it earlier, as I was afraid that the spoon could drop into it while setting up the composition.



Add some cherries (not earlier as I was afraid that they could start dripping), and increase exposure time from 1/4th of a second to 1/2 second.



Add some fill light on the front left in order to reduce shadows. I could have used a reflector, but I used a flash (wireless).




Increase the fill light power, once it is correctly positioned. As most of the light is still natural light, there is no real need to update white balance because of the fill-in flash.



Add a touch of style, and increase depth of field by 1 f-stop.



Increase exposure time from 1/2s to 1s.




And finally clone out those ugly reflections from the flash on the front of the plate.



(this picture is available within my 2010 pic-a-day gallery)]]> Photography http://gabriel.mp3-tech.org/blog/index.php?entry=entry100127-135749 Gabriel Bouvigne Wed, 27 Jan 2010 13:57:49 GMT http://gabriel.mp3-tech.org/blog/comments.php?y=10&m=01&entry=entry100127-135749 http://gabriel.mp3-tech.org/blog/index.php?entry=entry091223-152735

Here are a few shots from the Super-Multi-Coated Takumar 85/1.8 (M42 mount):













]]> Lenses http://gabriel.mp3-tech.org/blog/index.php?entry=entry091223-152735 Gabriel Bouvigne Wed, 23 Dec 2009 15:27:35 GMT http://gabriel.mp3-tech.org/blog/comments.php?y=09&m=12&entry=entry091223-152735 http://gabriel.mp3-tech.org/blog/index.php?entry=entry091122-110147

This 28mm f/2.8 MC Auto-Beroflex lens is a relatively small M42 mount lens featuring a maximum magnification ratio of 1:4 (higher magnification than a Sigma mini-wide which only goes to 1:6). While not exceptional, quality is quite good. Considering its low price, this is a very nice lens.









]]> Lenses http://gabriel.mp3-tech.org/blog/index.php?entry=entry091122-110147 Gabriel Bouvigne Sun, 22 Nov 2009 11:01:47 GMT http://gabriel.mp3-tech.org/blog/comments.php?y=09&m=11&entry=entry091122-110147 http://gabriel.mp3-tech.org/blog/index.php?entry=entry091102-141934

Here are a few shots from the "Porst color reflex mc auto" 55/1.2 lens, in Pentax K mount. This lens is built by Cosina, and features 6 optical elements in 6 groups (so it is different from the 55mm f/1.2 Tomioka lens in M42 mount which features 7 elements in 6 groups). Oddly, its aperture ring does not feature any stop between f/1.2 and f/2. All the shots are wide open (ie f/1.2)

In daylight, when shooting wide open this lens exhibit some kind of dreamy behavior:





At night, it does not exhibit this dreamy/fuzzy look unless there is significant light on the subject in focus:











]]> Lenses http://gabriel.mp3-tech.org/blog/index.php?entry=entry091102-141934 Gabriel Bouvigne Mon, 02 Nov 2009 14:19:34 GMT http://gabriel.mp3-tech.org/blog/comments.php?y=09&m=11&entry=entry091102-141934 http://gabriel.mp3-tech.org/blog/index.php?entry=entry091021-141303


(I actually own two copies of this 21mm lens: the Vivitar version and the Soligor version)













All the pictures are from my 2009 pic-a-day gallery.]]> Lenses http://gabriel.mp3-tech.org/blog/index.php?entry=entry091021-141303 Gabriel Bouvigne Wed, 21 Oct 2009 14:13:03 GMT http://gabriel.mp3-tech.org/blog/comments.php?y=09&m=10&entry=entry091021-141303 http://gabriel.mp3-tech.org/blog/index.php?entry=entry090902-102352


However, from an optical point of view, it is really surprising. A smooth bokeh wide open, quite robust against flare and very sharp once stopped down (even if wide open sharpness is already quite good). Krasnogorsky Zavod (the manufacturer) rates it as able to resolve 65/40 l/mm, while the supposedly very sharp MC Helios 44M-7 is only rated as able to resolve 50/30 l/mm.

It is available under the "Zenitar M2" and "Zenitar M2s" labels for the m42 version, and "Zenitar K2" for the K mount version:
KMZ page about this lens

Here are a few shots with it, from my 2009 Pic-A-Day gallery:









]]> Lenses http://gabriel.mp3-tech.org/blog/index.php?entry=entry090902-102352 Gabriel Bouvigne Wed, 02 Sep 2009 10:23:52 GMT http://gabriel.mp3-tech.org/blog/comments.php?y=09&m=09&entry=entry090902-102352 http://gabriel.mp3-tech.org/blog/index.php?entry=entry090824-162323
This lens optical schema is made of 7 elements in 3 groups. The diaphragm is located between the two triplets.


The front element can be accessed by unscrewing the front ring using a spanner:


The rear group can be unscrewed in a similar way, but it can not be directly removed from the lens barrel. However, if you set the lens to it minimum focus distance, you will be able to move the rear group inside the barrel. If you are very careful, that might be enough to allow you to clean it or the aperture blades.

Remove the rear ring by removing the side screw and unscrewing the ring:


You can now remove the focus ring:


That should be enough to allow you to access the focusing helicoid, by setting the lens to its minimal focus distance.

Now, remove the diaphragm ring:


From there, you can access the clicking mechanism of the preset aperture. If your aperture preset ring doesn't click properly, you might need to clean this small cylinder, or re-shape the metal part that sits on top of it.


You can now remove the aperture selection ring:


This allows you to remove the front part of the lens, which includes the front element and the front triplet. The front triplet can be removed by unscrewing this rear ring (using a spanner):
]]> Servicing http://gabriel.mp3-tech.org/blog/index.php?entry=entry090824-162323 Gabriel Bouvigne Mon, 24 Aug 2009 16:23:23 GMT http://gabriel.mp3-tech.org/blog/comments.php?y=09&m=08&entry=entry090824-162323 http://gabriel.mp3-tech.org/blog/index.php?entry=entry090729-100528 This one is branded as Ifbagon, but it is also available under the "Rollei - Design by Carl Zeiss" and "Voigtländer Color-Ultron" labels.



As its aperture is only designed to work in automatic stop down mode, it needs to be converted into manual mode to be usable on non-m42 cameras with an adapter.

First, set your lens to infinity and remove the four rear screws...


...and remove the mount.


Remove the outer black ring, and you can now remove those three screws:


One of those screw is longer than the other ones, as it acts as a stopper for the focusing mechanism. It is the one which goes on the bottom.


Here you can see the aperture transmission mechanism, which you should now remove.


The small cam is slightly asymmetric, so you can only put it back in one way.

Remove yet another ring in order to see the aperture mechanism.
Beware not to loose the small bearing and the spring which should be pressed on it.



The vertical cam of the diaphragm goes within the "fork" on the part we just removed. You can only put it back if the lens is focused at infinity.


You can now lock the aperture into manual position. I used a piece of insulator from an electric wire.


You should now be able to put everything back. If for any reason you goofed up by unscrewing the focusing helicoid, you can easily adjust infinity from the front of the lens.

Unscrew the front black ring, and you can access the three screws that will allow you to properly restore infinity setting.

]]> Servicing http://gabriel.mp3-tech.org/blog/index.php?entry=entry090729-100528 Gabriel Bouvigne Wed, 29 Jul 2009 10:05:28 GMT http://gabriel.mp3-tech.org/blog/comments.php?y=09&m=07&entry=entry090729-100528