PoukieBear
New member
I've been doing some reserach on macro lenses, and on the Sigma website, I found this realy cool picture, and it just happens to be related to the reef hobby!
Cool picture
- Thread starter PoukieBear
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PoukieBear
New member
When I first looked at it, I had no clue what it was. I thought it was some sort of techno shot! DOH!!
...I still haven't figured out all this macro lense stuff, ugh this is all so confusing.
...I still haven't figured out all this macro lense stuff, ugh this is all so confusing.
PoukieBear
New member
OK, first off, I know NOTHING about cameras and lenses. Zip, Zilch, Zero!
We have a Canon 20D and I love it because I can point and shoot and still get great shots with no effort required.
I tried to get the guy at the Henry's to explain to me in "stupid terms" what the differences are between all the lenses. 60mm lens and 100mm lens for instance. The only thing that I managed to get out of the guy is that the mm determines the distance of the subject away from the lens.
I don't understand the different field of views, or what the F2.5 or F3.8 part of the lens name is...or what an MTF chart is or why it's important.
What I really don't get (this is going to sound stupid to most of you) is the 1:1 and 1:2 life size. I know that 1:1 is actual life size and 1:2 is twice life size, but when you print the picture, it's not really going to be life size right? Because you're zoomed in so much, the object is going to seem huge compared to real life right?
Or am I just a hopeless case of Camera Stupid and I'll never understand this stuff?
We have a Canon 20D and I love it because I can point and shoot and still get great shots with no effort required.
I tried to get the guy at the Henry's to explain to me in "stupid terms" what the differences are between all the lenses. 60mm lens and 100mm lens for instance. The only thing that I managed to get out of the guy is that the mm determines the distance of the subject away from the lens.
I don't understand the different field of views, or what the F2.5 or F3.8 part of the lens name is...or what an MTF chart is or why it's important.
What I really don't get (this is going to sound stupid to most of you) is the 1:1 and 1:2 life size. I know that 1:1 is actual life size and 1:2 is twice life size, but when you print the picture, it's not really going to be life size right? Because you're zoomed in so much, the object is going to seem huge compared to real life right?
Or am I just a hopeless case of Camera Stupid and I'll never understand this stuff?
zenya
Premium Member
I think 1:2 means that the subject will be 1/2 of the life size and not twice life size( is such thing possible in a lens?).
Printing images has more to do with the resolution than the size of the subject, I think.
By the way, welcome to the Camera Stupid Club.., I'm the reigning President of it... :rollface:
Cutiewitbooty
New member
oh wow cool pic!
astrogazer
Premium Member
I'll try to handle your questions, and btw, there are no stupid questions if you aren't familiar with a subject.
As far as Focal length (mm of lens) you're basically talking magnification ratios 100-400mm zoom is said to have a 4:1 magnification ratio or a 4x zoom a 35-350mm would have a 10:1 ratio or 10x zoom.
It's not that the lens determins the distance as it is the distance determining the lens. If you were on saffari for example and wanted to take a picture of that 'cute' if not oversized kitty you would want a long focal length lens (500mm+) to keep as much distance between you and your subject as possible while not having a subject the size of a pinhead on the sensor. There are drawbacks to this magnification, but that's an entirely different chapter. As you magnify an image you will have a smaller Field of View (FOV) as is apparent if you look thru the viewfinder while zooming a lens out on your 20D.
The 2.5 and 3.8 issue .... what is being referred to here is the largest aperture (opening to admit light to the sensor) of the lens, the smaller the number the 'faster' the lens is said to be, it is said to be faster because with a larger diameter opening it can take an image with less light. Generally speaking higher quality lenses will have smaller numbers, ie. 1.8. MTF (Modulation Transfer Function) is one of the measurements that evaluate a lens' performance.
And lastly reproduction ratios, not to be confused with magnification ratios(above), a true macro lens is said to have a reproduction ratio of 1:1 (1 to 1), at a 1:1 ratio the subject imaged is lifesized on the sensor (or film), a 300 dpi printed output from my sensor is over 9" x 12", it will make anything MUCH larger than life, here's an example ...
PoukieBear
New member
Thanks so much for the info, that clears a lot of things up for me!
Lpabsolute
New member
Sweet Pic....
