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Old Feb 7, 2006, 9:06 PM   #1
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hey guys

Im looking at a few close up filters but i dont actually uderstand what they do. the one i am looking at has a factor of +1. which i have no idea what tht means and im wondering

1) do the filters distort the image in any way
2) What does the factor +1 mean and is higher better?
3) In the ad i see no mention of digicam so will these work ok on my fz30


thanks
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Old Feb 8, 2006, 8:25 AM   #2
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Close up filters (also known as macro filter)is the attempt to magnify the object you want to take a photo with and very often this effect is done by allowing the object be focused at a closer distance to the camera lens for a bigger image to be formed.

1) Yes, in order to bring the object closer some distortion might arise, like barrel distortion where the image is kind of deformed/swelled or, like more noticeable chromatic distortion with purple fringing observed on the edge of objects shot.

2) The +1, +2 ... markings are the diopter of the filter. The higher the value the bigger the power to magnify (or bring the object closer). Most cheap close up filters in the market often boost a very high diopter value, say +7 +10 etc. while the professional ones won't do so because cheaper never concern much about the results. Close up filters can also be stacked together to get higher power but with a drawback on a shortened farthiest focusable distance. That means with a very high power close up combo not only the closest focusable distance shortened but also the farthiest and causing quite a limitation on your photo composition.

3) Since the FZ30 is a BIG GUN with high zoom power, the achromatic doublet macro filters are highly recommended. Some popular models of this kind are the Nikon 5T [+1.5 diopter], 6T [+2.9 diopter] (for their 62mm filter thread size) and the Canon 250D [+4 diopter], 500D [+2 diopter](available in many different thread size up to 77mm). Comparing with the Hoya close up filter sets with only single glass elements, these Nikon and Canon achromatic filters have 2 elements professionally crafted tocompensate for the excessive chromaticdistortion and gives you much more decent images all around.

Rudolf.
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Old Feb 8, 2006, 2:31 PM   #3
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thanks for the in depth explanation



cheers
KEN


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Old Feb 9, 2006, 10:40 PM   #4
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Quote:
1) do the filters distort the image in any way
Normally, no distortion should occur. If you see distortion, which usually appears near the border of the image frame, it is basically due to the poorly design close-up lens and the distortion of the camera lens. Good close-up lenses usually have minimal distortion.

Quote:
2) What does the factor +1 mean and is higher better?

It is the so-called diopter value and is defined to be 1000/f, where f is the focal length of the close-up lens in mm. Therefore, a close-up lens of +4 has 250mm, and a close-up lens of 100mm has diopter +10. A higher diopter value means higher "magnification." If the camera lens is focused at infinite with a close-up lens mounted closely to the front element of the camera lens, the minimum working distance (i.e., the shortest distance from the front of the close-up lens to the subject) is approximately equal to the focal length of the close-up lens. This property is very useful. For example, if the camera lens has focal length F (the actual focal length rather than the 135 film equivalent) and if the close-up lens has focal length f, the magnification when the camera is focused at infinity is equal to F/f. Since the close-up lens' focal length is fixed,alongercamera focal length Fyields a higher magnification. For example, the maximum focal length of your FZ-30 is 88.88mm (the actual focal length rather than the 135 film equivalent) and a +4 close-up lens is being used. Since the +4 close-up lens has a focal length of 250mm, the magnification is 0.36X = 88.8/250, which a subject of 1 foot would appear as 0.36 foot on the image sensor.

Since the above calculation is based on single thin lens, actual magnification can vary but not by much. You can always determine the magnification of each close-up lens you have at the longest focal length of your camera. See my Canon A95 Information Page formore details.


3) In the ad i see no mention of digicam so will these work ok on my fz30


All close-up lenses can be used on any digital camera. But, the doublet ones will always produce better results. Those close-up lens kits (e.g., +1, +2 and +4) are mostly singlet (i.e., one glass element). Cheaper but excellent doublets are Nikon #3T +1.5 and #4T +2.9 (52mm thread) and #5T +1.5 and #6T +2.9 (62mm thread). In fact, most camera makers have their own doublet close-up lenses.

CK

http://www.cs.mtu.edu/~shene/DigiCam

Nikon 950/990/995/2500/4500/5700, Panasonic FZ-10/FZ-30, and Canon A95 User Guides





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Old Feb 10, 2006, 3:38 AM   #5
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woow thank you both for such in depth explanations. the close up i am getting is a +1 diopter. But its cheap it only cost me $15 Nz, so arnd $7 us.

thanks guys, if its good i might bid on a +4 diopter.



thanks

KEN

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