This^^Why does a focal length have to be good for something.
24-70 and 70-200 is just a focal range. They have to start and stop somewhere. Perhaps there is some scientific reason why they chose 70mm but who cares.
The types of photographers using zoom lenses (usually landscape) will zoom in and and out until they get the frame they want. They don't care if is 62mm, 68mm or 70mm and if they need more reach they switch to the longer focal range.
The only one I know of is the Pentax 70mm DA (for the crop cameras), guess that equates to 105mm which is a popular FL for headshots.
Zooms are usually worst at the extreme ends of their zoom range, so 70mm wouldn't be the best focal length zooms.What is a 70mm focal length "perfect" for?
I have not heard of many 70mm primes, yet plenty top class glass ends or starts with 70mm. 24-70, 70-200 etc.
Am I missing out on something?
Laws of physics certainly cannot be denied, but we also find with time that we just weren't too great pushing and bending them so far. Take a look at the new Sony 28-70mm f/2 GM. By all metrics including size and weight it obliterates a few year old massive and relatively soft design by Canon. This was considered "impossible" yet is available on the shelves today. In fact I find it rather tempting as long as I can find ways to account for its pricetagProblem is, laws of physics kick in and you end with something what is just too heavy to be practical for every day.
Presumably you are doing portrait and events work... This gets you nice full to maybe 3/4 length shots, small group shots, great in studio, not too great for subject isolation or long reach, certainly not ideal for headshots. It was always presumed you will have 70-200mm along to go longer whenever needed, ideally on a second body. Or as you mentioned any combination of longer primes...Personally I've always found 70mm on a 24-70mm to be too shot for my style of shooting, thats why I normally go for the 24-105mm or the ever so slightly longer 85mm prime (on FF) But that said we all shoot diferently (and I dont use the 85mm much if I'm honest).
Personally I've always found 70mm on a 24-70mm to be too shot for my style of shooting, thats why I normally go for the 24-105mm or the ever so slightly longer 85mm prime (on FF) But that said we all shoot diferently (and I dont use the 85mm much if I'm honest).
Yes I do always have a longer lens on a second body on a serious shootsPresumably you are doing portrait and events work... This gets you nice full to maybe 3/4 length shots, small group shots, great in studio, not too great for subject isolation or long reach, certainly not ideal for headshots. It was always presumed you will have 70-200mm along to go longer whenever needed, ideally on a second body. Or as you mentioned any combination of longer primes...
Now there is a choice of 2x-105 2.8 zooms and is arguably a better choice for some instead of the two conventional zooms. There is even 35-150 from tamron which is likely very questionable at the wider end, in any case more than the alternatives.
I rather now have 28, 35, 50 and 85mm f1.4 primes, so 70mm was a true pain point. I just had to get that sigma
A stop is a halving or doubling. Which means 24-50mm would be one stop not two as would 50-100mm.If you think of lenses as stops of focal length with 1 stop being 1.4x and 2 stops being 2x then you get the following series for the most common focal lengths (50mm=0)
24mm -2
35mm -1
50mm 0
70mm 1
100mm 2
135mm 3
200mm 4
If you use primes, this can be a useful way of thinking about lenses and the way things scale up when you change focal length.
I guess zooms were made to match the primes people had.
Focal length, like apertures, square when it is used to determine light levels. So doubling the focal length with the same aperture diameter would mean you increase the aperture number by 2 stops (eg from /2.8 to f/5.6). This makes sense dimensionally as the same amount of light spread over a rectangle which was 1/2 as big along each side would be 4 times brighter (2 stops).A stop is a halving or doubling. Which means 24-50mm would be one stop not two as would 50-100mm.
I’m not sure I see any benefit of thinking of focal lengths as stops.
Focal length, like apertures, square when it is used to determine light levels. So doubling the focal length with the same aperture diameter would mean you increase the aperture number by 2 stops (eg from /2.8 to f/5.6). This makes sense dimensionally as the same amount of light spread over a rectangle which was 1/2 as big along each side would be 4 times brighter (2 stops).