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.
1850441
I used 28-135 for more than 8 years and was happy with it. Recently, I purchased 24-105 and I was very surprised. AF is fast, image is clear, IS is working very good. 24-105 is excellent lens and much better than 28-135.
65715
I ordered the mask for my girlfriend who is near-sighted. She gave me a copy of her prescription. Under the "Dist" part of her prescription, sphere is -8.5 which is the number I used when I placed my mask order. I am assuming "DV" is distance, and "NV" is near. If so, I believe you would enter the "DV" number. The mask worked great for my girlfriend. She said she could see better out of the mask than her glasses. Hope that helps, Brian H.
64369
Because of the difference I would suggest buying 1 pair in each of the diopters you need and swapping out the lenses. For me the difference was only 1 point so I went up a half. They've worked out great.
1186462
My answer to this is to set the lens at F8 either with Aperture Priority or Manual Mode. Having the lens wide open at F 4.5 just doesn't give the best results IMO. The results of learning this lesson is in the early results of seeing soft images at the edges of the pictures and loss of sharpness. F8 makes all the difference with this lens at least for me.
678605
In my opinion it depends on what your main reason for using the lens is. If you don't NEED the 2.8 then go with the 4, I don't think IQ is dramatically better or worse. Unless there was ever a time while you were using the f/4 that you were like "man I wish I could stop down to 2.8," I would just stick to the f/4.Edit: Just saw on another reply you said something about portraits, if you are going to use the lens for portraits at all the 2.8 is amazing, the bokeh is simply stunning.
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.
2240578
I have had the 17-85 for a couple months and i already want to upgrade.. i want to sell it. i want the 17-40 f4 really bad. i would say unless dont mind about pictures that lack somewhat sharpness i would go with the 17-40. the 17-85 is hard to use i think.. of course unless you want mine ide sell it to you :)
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.
220609
Hi John,If light is an issue, you would definitely need a lens with f2.8 or less. and with 24-105 you can at best get f4.0 so I believe you will have to choose between quality and range.If you want quality in low light conditions then go for the 24-70 mm. If range is a greater priority then you can go for the 24-105 f/4.0 L IS
2136512
A fixed four will likely be cheaper and will work fine. With a 22 and its range, a 2x option would be good, but you will not need the magnification at 7x. If it were me, I would go for a fixed 4x for a 22. Hope this helps.
1177291
Depends on what your prescription is. The camera has a built in -3.0 to +1.0 diopter adjustment. You want to buy the one that will allow you to match your prescription.E.g. If you wear +2 prescription, get the +2 and dial it down by 1. You would only need the - if you have to go further than the -3 that is built in. However, I have found that I do not use the diopter. When I have my glasses off, the images on the LCD are blurry. So I shoot with my glasses or contacts, so I can still view the images on the LCD.Hope this helps you decide.Chris
77652
Yes, somebody here said +.2 or something like that.It is minor but present; makes screen seem just a little bit bigger.You can get them as prescription lenses if you need more.
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".
1984672
both .12 and .2 ! if u want farther reach use the .12 but if u want accuracy then u use .2.,, i prefer using .2's
1755638
Would really like to help with your question but, unfortunately, I didn't save the box or the instruction sheet. I can tell you however that these binoc's are great. I've used them on trips to Alaska and to China. I find very little "shake" or distortion at higher magnification compared with others that I looked at from the "brick and mortar" stores. If you purchase them I hope you are as satisfied with the product as I am.
960178
I'm having difficulty recalling as I use mine only at 0 deg. --- but it seems as if the choices were indeed only 0 and 90. EDIT: based upon consensus, I'm guessing that my previous comment is not correct!