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 Post subject: Optical zoom FZ-35
PostPosted: Sun Mar 07, 2010 11:20 am 
Good morning everyone !! (now 08h20min)

I was seeing in details (close up) my lens and I cant understand this information:

" DC VARIO-ELMARIT 1:2.8-4.4/4.8-86.4 ASPH LEICA "

Questions:

1. I know that aperture (f) my camera FZ-35 goes from 2.8 to 8.
Why they show only "2.8 - 4.4" ?

2. What is the meaning "ASPH" ?

3. Exist one way to check focal length (zoom) information in real time ?
I only find this information after take picture via metadata.

4. Getting these informations examples from .jpg (metadata):
f/4.4 - 529.0 (35mm film), 86.4 (lens)
f/4.0 - 62.0 (35mm film), 10.4 (lens)
f/3.6 - 107.0 (35mm film), 18.0 (lens)
f/2.8 - 30.0 (35mm film), 4.8 (lens) ... etc etc etc
How can I find conversion factor number from lens to 35mm film ?

Sorry about my bad english.
Cheers,
Carlos


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 Post subject:
PostPosted: Wed Mar 10, 2010 10:25 am 
Hi,
My guess is that the number written with 35mm film gives the equivalent focal length of the lens with a 35mm film camera, and the other value seems to be the actual distance from the sensor.
Since the fz35 is not a full frame camera, there is a field of view crop. This seems to be the conversion factor you mean. I am not sure about this, but I believe the field of view crop can be calculated by dividing the 35mm film value by the lens value. Thus irrespective of the actual distance from the sensor, it mentions that you would get this focal length on a 35mm sensor camera. I guess my explanation is a little complicated, but this is the best way I can put forth...
Your camera has a 27mm wide angle lens. Meaning at 2x, it will have equivalent of 54mm. Just check the 'x' by which you have zoomed and multiply it with 27 to get equivalent focal length. You will not be very accurate, but you can get a close approximation nonetheless. I think fz35 does not give the equivalent in real time, so you may have to do the math. If you want to know if it supports it in real time, the manual may be the best guide.
As for your question regarding f-numbers, I am not very sure, but it may have different limits in f-numbers at different zooms.
Hope this helps,
Jinay.


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 Post subject:
PostPosted: Wed Mar 10, 2010 12:02 pm 
Hello jinay ! Thank you for explanation.
I am thinking to buy one book !

Cheers,

Carlos


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 Post subject:
PostPosted: Wed Mar 10, 2010 2:14 pm 
Hi,

The f-numbers describe the largest possible aperture at the two extreme zoom values:

At full wide angle, the largest possible aperture (lowest f-number) is 2.8.
At full telephoto, the largest possible aperture is 4.4

The full aperture range is therefore only available at full wide angle. What is just as important, is how much light the lens can gather at each focal length, and therefore the two limit values are specified on the lens.

As far as "ASPH" is concerned, I think this refers to aspherical lens elements.

[EDIT: jinay, could you explain what you mean by a "full frame camera"?]

Regards,
Mark


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 Post subject:
PostPosted: Wed Mar 10, 2010 5:36 pm 
"A full-frame digital SLR is a digital single-lens reflex camera (DSLR) fitted
with an image sensor that is the same size as a 35 mm (36x24 mm) film frame".
Basically one would be looking at spending many thousands of dollars to get one.
i.e Sony A850, Nikon D3S, Canon EOS 5D Mark II etc.
Regards


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 Post subject:
PostPosted: Sat Mar 13, 2010 1:48 am 
I took some pictures in 27 mm wide and notice a "geometry" problem.
I think caused lens. Exist one way to solve to reduce this effect ? (at left and right looks building are not in line, or vertical.
Really is good deal 27mm wide-angle lens but not like this.

Picture with problem:

http://www.4shared.com/file/240047734/3 ... 10119.html

Image Type: jpeg (The JPEG image format)
Width: 4000 pixels
Height: 2248 pixels
Camera Brand: Panasonic
Camera Model: DMC-FZ35
Date Taken: 2010:02:09 17:49:16
Exposure Time: 1/640 sec.
ISO Speed Rating: 80
Flash Fired: Flash did not fire, compulsory flash mode.
Metering Mode: Pattern
Exposure Program: Aperture priority
Focal Length: 4.8 mm
Software: Ver.1.0

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Picture more zoom and no problem:

http://www.4shared.com/file/240050225/f ... 10151.html

Image Type: jpeg (The JPEG image format)
Width: 4000 pixels
Height: 2248 pixels
Camera Brand: Panasonic
Camera Model: DMC-FZ35
Date Taken: 2010:02:09 18:20:37
Exposure Time: 1/100 sec.
ISO Speed Rating: 100
Flash Fired: Flash did not fire, compulsory flash mode.
Metering Mode: Pattern
Exposure Program: Aperture priority
Focal Length: 23.7 mm
Software: Ver.1.0


Cheers,

Carlos

ps: sorry about my bad english


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 Post subject:
PostPosted: Sat Mar 13, 2010 12:04 pm 
Offline

Joined: Sat Dec 26, 2009 11:45 am
Posts: 143
Hello Carlos,

As Mark has correctly mentioned, the numbers 1:2.8 - 4.4/4.8 - 86.4 does refer to the maximum aperture you can have at the 2 extremes of the lense. That is f2.8 at 4.8mm (27mm -35mm format) and f4.4 at 86.4mm (486mm - 35mm format).
The camera can stop down to f8 means that you can narrow down the aperture till f8 but max. aperture (widest opening possible) can only be f4.4 at longest tele end.
Also the conversion to 35mm format can be had by multiplying the focal length of FZ35 with 5.625. example- shortest focal lenthg is 4.8mm => 4.8 x 5.625 = 27mm and; longest focal lenthg at 86.4mm => 86.4 x 5.625 = 486mm.
May be you can re-check the 35mm conversions mentioned in your previous post.
ASPH does stand for aspherical lense elements.

The inclination of buildings happening at 27mm may be due to barrel distortion but not sure on this.

Rgds,

_________________
Jagadish_C
http://www.flickr.com/photos/89030952@N04/
http://s1229.photobucket.com/albums/ee472/Jagadish_c/
http://www.flickr.com/photos/46710427@N07/


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PostPosted: Sat Mar 13, 2010 9:52 pm 
Hello Jagadish_C !

Thank you very much about explanations !
I found a lot information at " http://en.wikipedia.org/wiki/Distortion_%28optics%29 " about Barrel distortion.
I think that solution is not use 27mm because looks strange like this pic at wikipedia.

http://en.wikipedia.org/wiki/File:St._H ... h_side.jpg

Regards,

Carlos


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 Post subject:
PostPosted: Sun Mar 14, 2010 8:11 am 
Offline

Joined: Sat Dec 26, 2009 11:45 am
Posts: 143
Hello Carlos,

Happy that to know that the info was of use.
Yes, as mentioned in wiki, same effect is seen in your photo too.
Oh Boy!!! That correction formula made all my A, B, C of photography go X, Y, Z :shock:
But on the other hand, you can use 27mm. BD Problem will be more visible if you try to shoot some oblects which are at very far distance and having much height. Give a try at 27mm for some thing within say 30 mts and check. Should be OK I guess.

Regards,

_________________
Jagadish_C
http://www.flickr.com/photos/89030952@N04/
http://s1229.photobucket.com/albums/ee472/Jagadish_c/
http://www.flickr.com/photos/46710427@N07/


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 Profile  
 
PostPosted: Sun Mar 14, 2010 1:06 pm 
Hello Jagadish_C !

One question: How did you find crop factor number (5,625) ? Did you use some value of sensor size of FZ 35 ?

Regards,

Carlos


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 Post subject:
PostPosted: Sun Mar 14, 2010 5:06 pm 
Offline

Joined: Sat Dec 26, 2009 11:45 am
Posts: 143
Hello Carlos,

5.625 can be obtained by dividing the diagonal for a 35mm (film) full frame sensor which is 43mm by diagonal for FZ35 sensor which is 7.64mm (approx). 43/7.64 = 5.625(approx)

Another feature of FZ35 you might like which is the Enhanced Zoom (EZ).
It hepls you to zoom in more than 18X but to get this the resolution must be reduced from 12MP. As Gordon explained to one of my questions, the camera uses extra mega pix I sacrifice by reducing from 12MP to boost up the image captured. Any zoom above 18X is not optical but intelligent digital. You can try 1 thing....shoot a subject at 12MP resolution and 18X. Then try the same shot with reduced MP and increased zoom (more than 18X). The second shot will give you same pic size and quality as if you cropped the 12MP pic.
If you find any difference in image quality (IQ) do let me know and I will have a word or two to discuss with Panasonic :twisted:

Regards,

_________________
Jagadish_C
http://www.flickr.com/photos/89030952@N04/
http://s1229.photobucket.com/albums/ee472/Jagadish_c/
http://www.flickr.com/photos/46710427@N07/


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 Profile  
 
 Post subject:
PostPosted: Wed Mar 17, 2010 4:38 am 
Hi,

Sorry for the late reply...

Mark R., my interpretation of "full frame" is same as dbnnet's....

cameks, some softwares can help reduce the lens effects to some extent. Helicon Filter is an example. You may not get a perfect image, but it should help. I normally try to keep the tall structures in the centre of the image to reduce this effect. You can also try to keep your camera perfectly straight to minimize this, i.e. its base parallel to the ground....

Hope this helps,
Jinay


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 Post subject:
PostPosted: Mon Mar 22, 2010 12:34 am 
Hi jinay ! Thanks for information
I have other question, how to clean my lens ?
I got some very few rain in lens .. and now I have little circle spot.

Cheers,

Carlos

ps: I read at internet that best choice is use cotton and isopropyl alcohol. But sounds strange for me ...

Any idea ?


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 Post subject:
PostPosted: Mon Mar 22, 2010 1:31 am 
Hi again,
I'd say your local camera shop can be the best guide! You should find a cleaning kit, or some may take your camera for servicing too. But to protect the lens, maybe you should always use a UV filter. A good quality one should make no difference to photo quality, and can remain on the lens even when the camera is switched off.
Hope this helps,
Jinay.


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 Post subject:
PostPosted: Mon Mar 22, 2010 6:13 am 
jinay wrote:
....maybe you should always use a UV filter...... remain on the lens even when the camera is switched off.

I could not agree more: I really think this is a MUST DO!
I have used a uv filter since I bought my FZ38/35 and its never been taken
off since.
Regards


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