Sorry, I'm a bit puzzled. What's the difference between -4.0 and -4? I'm from China and 400 degrees of myopia. Should I choose -4.0 or -4 or 4?
82129
I think -4.0 and -4 are the same. If you are near-sighted, you should choose negative.
770501
Some have different colors like azure(blue) on the inside frame and black outside so it has to do with the color and also GR004 gives you the option to include magnification on the lenses if you want or need that. You can look at the description of each to see if its the one you want. You can choose no magnification on the ones that offer it and the only difference would be the color.
1747
These numbers refer to the strength (magnification) of the lenses. Higher numbers magnify more.
1503374
The 25 and 36 refer to the size of the lens opposite the eyepiece in mm. The larger the lens the more light it gathers. This of course makes for a heavier monocular and a larger one. I have a 10x25 and it is fine. You have to have a steady hand though in using the devise.
108095
If there is a f/1.8 option by Nikon (there isn't as I type this) then it'll most definitely be lighter in weight and maybe 7 aperture blades vs. 9 on the f/1.4G. It won't have weather sealing like the f/1.4G version. Might be sharper than the f/1.4G though and most likely will be better corrected since it's a newer version. The difference in speed, though, might be big as it's the difference between shooting at 1/30 and 1/60. If we're talking a different manufacturer then all bets are off as they might have different specs.
108097
This represents approximately 1/2 stop of light. That may not sound like much but in low light it can make a difference. Also, Nikon doesn't make a 24mm 1.8. the closest is a 28mm 1.8 which is obviously a different focal length. It is a very good lens however. If you don't need the 1.4 and 28mm is an acceptable focal length then go for that as it is much cheaper.
473926
I'm getting ready to order the 400mm. I already have the 70-200L 2.8 IS and if I wanted the extra reach with zoom, I could put my 1.4x teleconverter on it, making it a [roughly] 100-280 f4.0. I don't have the 100-400 to compare, but I'd guess the sharpness is about the same between the 100-400 and the 70-200 + 1.4x. I still wouldn't have the reach between 280-400 but I'd have the sharpness when I need it. I can always attempt to move my feet to frame a subject with a prime if I'm too close. Read the reviews and decide for yourself.
2166157
The 1.4 on the lens refers to how low the aperture goes. Aperture is how large or small the opening in the lens is and you can change it to control depth of field. This lens goes down to a 1.4 which is a really low number meaning a really LARGE opening in the lens allowing for a super shallow depth of field which can create those dreamy "blurry" backgrounds that people love.
2240584
I have the 17-40 and the 17-55 IS. I thought I would sell the 17-40 once I got the 17-55 but I can't. I have decided to keep both. The color saturation and clarity is excellent on both. For now I'm holding on to both of them. They are that good.
1939951
f 1.4. You can take photos in lower light than the 1.8. Just an FYI, if I had to do it again, I would have bought a 35 mm 1.4 instead of the 50 mm.
187070
I was not sure when I first looked, then I realized the different models had different temperature capabilities, and if I recall some of them had different focus ratio as well. Keeping this in mind, Read descriptions carefully, the differences will be more apparent!
1588421
I purchased the 1.4X, after doing research on the results of both products. From what I read, the images stay "sharper" at the edges, with the 1.4x. I have used the 1.4X, and have been very pleased with the results. I do intend to purchase the 2x, understanding that the clarity may not be as good.
1069237
Sharper by a discernible amount. Lighter! Faster focusing. 70-300 maintains a significant advantage in close focusing though. I have both lenses. If you want to shoot bugs and flowers, 70-300 is the way to go. Birds, sports, the moon, 75-300.
107885
Go higher! under water there is less visibility, so anything that gives you the edge, I would go for... Anyway there is some eye adjustment at any point and at that level half a Dioptric is almost negligible (my unprofessional opinion)
49300
You need to know your glasses prescription. If you're nearsighted, (need correction for distance sight your rx will be a negative number. The lenses come in 0.5 increments. For example I have a -3.75 correction. Since it is in between correction options I ordered a -3.50. (If your in between order the lesser strength). If you are far sighted the correction will be a +.(ie reading glasses). Hope that helps.
1625584
The difference is 1mm wider on the wide end and doesn't have as wide of a zoom range (8mm less on the long end). In exchange for a very limited zoom range, you get 1 stop more light to your sensor.I have the 11-16mm and wouldn't trade it for the 12-24 unless I needed more overlap with my other lenses. As it is right now, I have nice coverage from 11-200 with only small gaps (16-17mm and 55-70mm) and a constant f/2.8 or better.
2041777
First, size. The 1.2 is huge! And the reason is also the second thing, optics. Unless you have a huge need, budget or ego, don't go 1.2. The 1.4 is amazing but the price may make you feel insecure, like it's not "good enough".