35mm vs. 50mm & 50mm vs. 85mm

Hello everyone,


I have been reading your posts for some time and have picked up quite a bit. Thanks for that.


My question concerns prime lenses. I have read many places that the 35mm, 50mm and 85mm lenses are very valuable. I understand the usefulness of wide apertures for low light and great D.O.F. Are you looking for those exact focal lengths or in the area? The reason I ask is because I use a cropped sensor and if I were to want a 50mm focal length I would most likely go for the 35mm f/2 (or something like it) for a 1.6x conversion of 56mm. Like wise if I wanted an 85mm I would go for the 50mm f/1.4 to get 80mm. I figure I would use them for general photography including low light. Are you recommending the 50mm and 85mm because of the particular lenses or because of the benefits of the focal lengths?


Thanks,


Brett

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Originally Posted by LDH01

Are you recommending the 50mm and 85mm because of the particular lenses or because of the benefits of the focal lengths?

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Our recommendations are usually based on both. First and foremost, you'll need to know what focal length your particular needs require. Both the 50mm and 85mm lenses are almost useless in tight quarters. In fact, I've found the 35 f/2 to be a bit tight indoors at times--but to me, it's more certainly more useful in those situations. However, the 35mm f/2's build quality is terrible in comparison to, let's say, the 85mm f/1.8. Therefore, if an 85mm lens would suit your needs the same as or better than a 35mm lens, you'd be a fool to purchase the 35mm f/2.


I own the 35mm f/2, the 50mm f/1.4, and the 85mm f/1.8. While I find that the 85mm f/1.8 turns out better image quality, its focal length is less useful to me than the 50mm f/1.4. The 35mm focal length is probably most useful to me, but the image and build qualities lead me to use the 50mm lens whenever I can get away with it. So, for my needs, the 50mm f/1.4 is the best compromise of the three lenses--and therefore gets used the most.

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Originally Posted by LDH01

Are you recommending the 50mm and 85mm because of the particular lenses or because of the benefits of the focal lengths?

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Hi Brett,


My recommendations are usually based on a combination of the two, but weighted heavily toward focal length. That makes sense - for example, if you're taking a pictures inside a 10x12 foot room with a 1.6x body, the best 85mm lens will not allow you to take a group shot. There's a pretty substantial difference between 50mm and 85mm. On a crop body, 35-50mm is good for full body portraits, for example, while 85mm is good for tight portraits (head shots, etc.).


So if you want a prime for the wide aperture, how do you choose the focal length? If you have a zoom covering that range, shoot with it set to various lengths, or look back over your EXIF data to see where your shots were taken. Else, guess based on comparisons to lenses you do have, or rent a lens if you like.


As a general rule, decide which focal length(s) you want/need, then get the best quality lens at the chosen focal length(s) that your budget permits. There are some nuances in there - for example, the 35mm f/2 is not the best quality (optically or build), the 50mm f/1.4 is pretty good for both, and the 85mm f/1.8 is excellent for IQ and very good for build.


Hope that helps...


--John

Well said Neuro.

Thanks John and Sean.


What you have said does make sense. Just like every lens purchase I will need to weigh out it

My primary camera is a Canon 7D; my backup is a 50D. Both are crop sensors.


And, speaking of the 50mm f/1.4, I used it Thurs night for this shot:





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Sean,


Looks sharp. Good example. Especially due to the fact that a 7D is top of my Wish List.


Brett

The 50mm f/1.4 is a sharp lens--but not at f/1.4. The picture above was taken at f/4.5.

LDH01, I agree that the image Sean posted is a good example, but personally I try to be a little more careful about how I draw conclusions about sharpness from web images. It

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Originally Posted by Daniel Browning

That said, it is definitely a sharp lens at about two stops down from wide open.
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Reading discussions on the 50 f1.4 it sounds like there may be variations in copies. I think I got a good copy. Here is 100% crop, wide open, very minimal sharpening.


[img]/resized-image.ashx/__size/800x600/__key/CommunityServer-Discussions-Components-Files/8/0272.IMG_5F00_0014.JPG[/img]


Camera Maker: Canon
Camera Model: Canon EOS 5D
Image Date: 2010-10-09 12:35:31 -0500
Focal Length: 50.0mm
Aperture: f/1.4
Exposure Time: 0.0010 s (1/1000)
ISO equiv: 50
Exposure Bias: +0.67 EV
White Balance: Auto
Flash Fired: No (Manual)
Color Space: sRGB v1.31 (Canon)


at f2.8 or f4 it is really sharp. I like this lens


Mark

If you need to stop this lens down to f/4 to get good sharpness than what are it

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Originally Posted by LDH01

If you need to stop this lens down to f/4 to get good sharpness

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By f/2.8 the 50mm f/1.4 it's noticeably sharper than the 24-70.

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Originally Posted by LDH01

than what are it's advantages over my 24-70 f/2.8 besides size and weight?

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For me, the primary advantages are control over DOF and low light photography, either of which can be more important than sharpness. There can be other benefits as well, such as less distortion, vignetting, bokeh, flare, etc. (In the case of this lens, however, few of those apply.) This has to be weighed against the flexibility of zooming of course. Generally, I tend to use the 50mm f/1.4 wide open when the subject has low contrast (low dynamic range), such as in studio flash setups. If the scene has a lot of dynamic range (high contrast), I'll stop down to f/2.8 because I dislike the flare/halation.

So the lens is sharp and has several others strong points and a few weaker areas, but what lens doesn