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House of Laughter

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I really really want to buy a macro lens but can't spend more than $400 - I am clueless about the mm and all the numbers

Educate me, PLEASE!

See pics for desperation shots!

House
 

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sanjay

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Jim;

With lenses, it often - you get what you pay for.

A true macro lens implies that you will be able to get 1:1 reproduction. What that means is that if the object is 2 mm in size in real life it will be 2 mm on your camera sensor. However you will only get that 1:1 ratio. However, you will only get that only at smallest distance the lens can focus at. For example, fo rmy 105 mm lens, to get 1:1 reproduction the object has to be 1 ft from the focal length. A smaller focal length lens like a 60 mm lens, will give you 1:1 at smaller distances.

Both the 60mm and 105 mm lenses will be fine, but I prefer the 105 mm lens. Get the sigma 105 macro, if you want to save some money. Its a good lens for most of what you would want to do.

You should invest in a good tripod if you want to take macro pics. When taking macro pics you will often be limited by the light available, and that will force you into slower shutter speeds making it difficult to hold the camera steady enough, resulting in a blurry shot.

If you have any other questions let me know.

sanjay.


I think you have a nikon d40, right ?
 

House of Laughter

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Sanjay - see, I knew an engineer would make sense of this for me :) =- now I understand what all the damn numbers mean in ENGLISH!!

I would say I am within a foot when taking macro shots - I intend to do some stuff with flowers (yeah right) or corals :bigsmile:

I do have the D40 and am hoping for one that auto-focuses

I'll look at the sigma

Thanks again!

Jim
 

sanjay

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Here is a link to the Sigma 105 mm macro lens

http://www.bhphotovideo.com/c/product/341922-USA/Sigma_257306_105mm_f_2_8_EX_Macro.html

And here is the Nikon version, with VR (vibration reduction build into the lens).

http://www.bhphotovideo.com/c/product/424744-USA/Nikon_2160_105mm_f_2_8G_ED_IF_AF_S.html

As you can see the Sigma is considerably cheaper, but still a good lens.

These are both autofocus lenses, and will also allow manual focusing. For macro photos sometime manual focus works better.

The other number 2.8 relates to the aperture opening. With apertures, smaller the number means larger the aperture, and hence lets more light in. So a f22 would be a small aperture and F2.8 would be a larger aperture. The aperture is also important in controlling the Depth of Field or Depth of focus. When you take picutures, there is a certain range of distance within which the picture will be in focus. This is called depth of focus. Anything else in front or behind it will be out of focus and blurry. The smaller the aperture (ie larger F number) the larger the depth of focus you can get.

And ofcourse the smaller the aperture, the less light reaches the sensor. You can compensate for that in several ways, each with its own trade offs.
1) use a flash... but for macros the overhead flash or camera flash may not work well since you are too close to your subject and the light gets blocked by the camera.
2) use a slower shutter speed. This lets more light reach the sensor, but at slow speeds its almost impossible to hold the camera steady, hence the need for a good tripod.
3) Use a higher film speed setting - called ISO number. The trade off here is that with higher ISO number, your picture will get grainier. Ofcourse this is lately not true with the new Nikon D3 camera.

So as you can see you have several controls (aperture, shutter speed, and ISO settings, flash/no flash) to control the light and each comes with its own limitations and constraints.

sanjay.
 

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