why is a 50mm a must have?

[jjphoto]

...

Speaking of the 50mm 1.2... is there a point in having a lens that goes that wide? The DOF is so shallow as to be nigh impossible to use - I have a hard enough time at 1.8.

The difference between F1.4 and F1.2 is some where between a 1/3 to a 1/2 stop. It's a significant and worthwhile difference but an F1.2 doesn't become much more difficult to focus or use than an F1.4 lens (not withstanding some possible further softeneing of the image when wide open which makes manual focusing a little harder still). I'm a big fan of fast lenses and will always choose a fast lens over a slow one, for many reasons, and you can always stop down a fast lens if you need to.

JJ

[Kym]

It should be that everyone should have at least one 50mm prime fast lens !

[ameerat42]

The difference between F1.4 and F1.2 is some where between a 1/3 to a 1/2 stop. It's a significant and worthwhile difference but an F1.2 doesn't become much more difficult to focus or use than an F1.4 lens (not withstanding some possible further softeneing of the image when wide open which makes manual focusing a little harder still). I'm a big fan of fast lenses and will always choose a fast lens over a slow one, for many reasons, and you can always stop down a fast lens if you need to.

JJ

That's about right. f/1 to f/1.4 is one stop.
Am.

[Xenedis]

It should be that everyone should have at least one 50mm prime fast lens !

I have four fast prime lenses: 35/1.4, 85/1.2, 135/2 and 300/2.8.

Note the lack of 50mm. :-D

[Xenedis]

The difference between F1.4 and F1.2 is some where between a 1/3 to a 1/2 stop.

f/1.2 is a half-stop interval.

[arthurking83]

f/1.2 is a half-stop interval.

Not exactly.

JJ is correct, in that it's somewhere between 1/3rd and 1/2 stop.

The value f/1.2 is used as both a 1/3 and also 1/2 stop value difference.

It's due to the rounding factor, it's rounded both up and down depending of use.

1/3rd stops aperture stops from f/1.0 are:

f/1.0, f/1.1 and then f/1.2(actual number being f/1.259) to go on to the full stop at f/1.4 ...

But .... if you then use half stop intervals from f/1.0 you also get:

f/1.0, f/1.2(actual number being f/1.189) and then f/1.4.

The formula is based on a square root of 2 value.

mathematically speaking it is closer to 1/2 stop in terms of a more accurate exposure, as the rounding factor is smaller at the 1/2 stop interval compared to the 1/3rd interval.


but!! ..... knowing how much more power the marketing departments wield over the engineering folks have at any manufacturer, you can also bet that this actual physical size of the aperture is going to be closer to the 1/3 stop rounded value than it is to the 1/2 stop rounded value.

[Steve Axford]

Ah - but is the actual fstop f1.259? And it is just the displayed fstop that is f1.2? It may be much easier to engineer the fstops to 1/2 or 1/3 rather than the displayed or marketing values.

[jdreamer]

I used to have both 35mm and 50mm which I found 35mm to be more suitable to what I normally shot. However, 50mm is certainly a lens that comes in handy!

[Kym]

While on f/stops... The library has the gory details for the new members...

http://www.ausphotography.net.au/for...y:f_stop_chart
and
http://www.ausphotography.net.au/for...SO_Sensitivity

[patrickv]

I'm a bit surprised ... No love for the 50mm !! All zooms !!
The 50mm (or the 30 to 35 equivalent for small sensors) is my favourite all time lens.
What I photograph with it just looks right. If I had to have only one lens, I'd definitely go with this one.

Sure, I'm old school, I was processing my Tri-X in the 80s ...

The 50mm looks right, as a viewer it feels "just as if I was there". This is very compelling for a photo that brings emotion to the viewer, not some "special visual effect" shot ...

For me, changing focal length to compose is a terrible lazy habit. Whenever possible, the perspective should be a deliberate thing. Sure, there are a few cases that don't give you much choice, such as interiors (need wide or you won't see anything) and sports/wildlife (you can't approach) but as a general thing it feels much better to use a "normal lens".

But just imagine a photo of some wide animal with a 50mm perspective, or even slightly wild angle. You're not a long distance observer any more, you're right there and it feels like you're just there. It would make a spectacular image.

I like the "wide animal" and "wild angle" mixup. I'll leave it in.

[Kym]

@patrick - Perspective!! Yes!!

Even if you use a zoom lens, changing the perspective with your feet is absolutely needed!

[KeeFy]

Speaking of the 50mm 1.2... is there a point in having a lens that goes that wide? The DOF is so shallow as to be nigh impossible to use - I have a hard enough time at 1.8.

If you are taking photo of a scene/subject up close, then natrually you'll have issues. Once you move further away like 2+ 3m. It's really easy and the DOF is shallow enough for the subject to be in focus (like a person) and blur out the back scene.

I do however agree it's hard to use the 50 f1.2 on a crop sensor and i had some issues using it with the 7D.





Both shot at f1.2 with a 5D classic.

Keith

[LJG]

This thread is interesting reading. I have had 3 50mm lenses over the years. The Canon f1.8, then the Canon f1.4, now I have the Sigma f1.4. Whenever I shoot people I either use my Sigma 50mm or my Sigma 85mm f1.4. I like the suject seperation a narrow depth of field has. I also think having a fixed focal length can be more fun to use and makes you think that bit more about composing your shot, rather than just standing stationary and zooming in or out. They can be a lot of fun to use, but are they a must have? That comes down to personal preference.

[Terri]

Interesting thread. It caught my attention. I too have a 50mm "because everyone said you should" ha! I too have found very little use for it - and have had very little success the few times I have used it. I'm sure it's me, not the lens. I use my 35mm heaps more.

[mikec]

@ patrick and kym

Completely agree, I find I usually use my zoom's like a prime. I'll get the approximate focal length I want and just walk back and forth to frame. Only time I really take advantage of zooms is when I can't move eg. hanging on a rope doing climbing shots.

I like being able to quickly shoot an 85mm head and shoulder shot then get in at like 135mm for a closer detail shot with a consistent and considered perspective. This is particularly import for a typology series I'm doing at uni at the moment.

[ving]

read kyms post.

basically you dont need it, no one needs on but they are good to have.

[Lazyshooter]

I have a 50mm prime and I actually use it quite regularly. I like the focal length on the crop sensor and has the advantages over standard zooms in that it is 1) smaller and 2) faster. My tip would be to get your zoom and set it to 35mm or 50mm and go and take some photos at that focal length, see what works for you.

[patrickv]

Interesting thread. It caught my attention. I too have a 50mm "because everyone said you should" ha! I too have found very little use for it - and have had very little success the few times I have used it. I'm sure it's me, not the lens. I use my 35mm heaps more.

The "you should use a 50mm" saying originates from when everyone mostly used 35mm film (ie. full frame cameras), which is actually not so long ago, approximately ten years.
As technology advanced, camera makers started to make digital cameras. At first it was so challenging that they couldn't make a single decent 35mm size sensor at all without messing up thousands of them. What they did manage was to make smaller sensors, 1.5x times smaller (Nikon) and 1.6x times smaller (Canon). Technology improved and at last in the five last years ago they were able to make bigger sensors (D3, 2007), but it's still extremely costly because of the reject numbers. Anyway, this means that most consumer cameras have a smaller sensor than the regular 35mm film equivalent.

The actual 50mm number means nothing by itself. It only has signification when combined with a sensor/film size. When people started to say (rightfully) that we should use a 50mm, practically everyone used the same size sensor: the regular 35mm. The saying has remained, but now most people have a camera with a smaller sensor.

The real meaning of this saying is actually "you should use a lens that gives you a 39.6 x 27 angle of view" because it's similar to eyesight. On film or on FX, it translates to 50mm. On DX it translates to 50 divided by the smaller surface, which is 33.3. Therefore your 35mm is actually providing a "50mm equivalent perspective" and you are doing exactly what is recommended.

For Canon it's 1.6x and not 1.5x so the closest approximation is more 30mm. Canon don't make a 30mm prime lens, they only make a 35 f/2 and a 35 f/1.4L so to have a "normal perspective" on Canon crop, I would rather recommend the Sigma 50mm F1.4 EX DC HSM lens. It's a beautiful lens, crisp, very fast, nice bokeh, not too expensive. They sometimes have autofocus issues (calibration) but you just have to bring them to warranty and it will be OK within a few days.

For a DX/Crop sensor (most of us), a 50mm becomes a portrait lens. It's still good to have but it's definitely not an all-rounder.

Cheers.

[Lance B]

As people have suggested, the 50mm lens being a "must have" is from the 35mm SLR film days when it was sold as the standard lens with every camera, now the standard lens is the kit zoom. The DSLR kit zoom is usually a focal length range from 17 or 18mm - 50 or 70mm or thereabouts on cropped sensor camera (APS C or DX) and 24mm - 70mm or thereabouts on a FF camera. These zooms incorporate the standard focal length for their respective formats in that zoom range.

The beauty of the 50mm lens nowadays is that it serves two purposes and hence why it is probably still reasonably popular and that is that on FF it is the "standard" lens but on a cropped sensor camera (APS C or DX) it becomes a very wide aperture portrait lens.

As for a "must have", it depends on what you shoot. As I shoot with a FF camera, I rarely use focal lengths around the 50mm mark except maybe a few times when taking holiday snaps with my 24-70 zoom. In fact, mostly I am shooting either at the extreme wide end or at the long end of the 24-70.

[zollo]

most already know, but 50mm is not similar to eyesight as most would experience everyday. 50mm is equivalent to only one eye open. As in close one eye, and thats equal to 50mm. The actual width of lens that is closely equivalent to what we can make out with both eyes open is 24mm, before it becomes blurred peripheral vision.

Which is why I much prefer either a 35mm or 28mm prime lens, for walk around/holiday style shots, and for environmental portraits too. 28mm is probably my favourite, as it gives a natural feel, whereas the 50mm feels slightly telephoto to me. Of course there will be more distortion at 28 than 50, but shoot it correct and on a prime you should still be able to get away with it.