zoom lens vs prime lens for portraits

[David Kwok]

Prove me that i m wrong then, that's if you could. Prove to me that the colours on 70-300 can be made the same as 300 f2.8.

If not, this would be the best joke for all the 300 2.8 owners in the world!

There is nothing here to be proven wrong. Your conclusion is right, 300 f/2.8 of higher quality than 70-300 f/4-5.6. But what Rashkae is amused at how you come to that conclusion. Go learn how to read a MTF Chart.

There are multiple factors attributing to the quality of the image produced by any lens, but if we place some reasonable doubts like the manufacturer QC, the preservation and handling of the actual equipment, then it all boils down to reading the chart and knowing the tested quality of the lens.

Also even if the quality are comparable, each design and material of the lens and coating will influence the colour of the light passing through it.

There is no reason to believe prime must be better, it's just there are reasons to believe they are better due to less complicated design in the lens, less movable parts etc. There are zooms better than primes for example, you will find the Nikon 14-24 f/2.8 much better in built, design and imaging compared some older primes. Here the most obvious is of course technology. I would believe it's definitely a technical challenge to get a zoom lens of same or better quality than a prime. Question is a prime only have focal length to manage, a zoom has a range of continuous range to manage. Are you prepared to pay probable a few thousands percents more for the cost of a zoom to achieve the same quality as the prime lens ? Also are you prepared to hold a much heavier and longer lens ?

Go read the following links
Nikon | Imaging Products | AF Zoom-Nikkor 70-300mm f/4-5.6G (4.3x)
Nikon | Imaging Products | AF-S NIKKOR 300mm f/2.8G ED VR II

 

[area0404]

Woah. There are a couple of ideas that don't seem right though.

1. Less glass doesn't mean better image quality. It does, however, generally speaking, lead to better light transmission. You may search up f-values and t-values to have a better understanding of this.

2. Prime lenses are not always cheaper. Just look at the f/1.4 primes and the telephoto primes.

3. Primes aren't always smaller and lighter either. Go check out the 200mm f/2 or the 300mm f/2.8. They are way larger than most zooms.

Ah, I am sorry that I forgot to elaborate on some constants.

1. Less glass (providing they are of similar quality) means less light dispersion due to refraction, so in my opinion (not 100% due to lens design and many other factors) less glass means better IQ. And of course, there are a whole range of different types of glass that compensate for refraction or do other wonders which complicate the matter further.

2. Provided of similar quality, yes I believe they are cheaper. A 50mm 1.4 will almost always be cheaper than a zoom lens that can shoot at 50mm 1.4 unless their quality differs greatly.

3. Again, I forgot to state the fact that the zoom lens must be able to cover the range of the prime (which don't happen very often) and image quality shouldn't differ greatly. Prime is almost always smaller and lighter.

Hope that clears the air.

EDIT: And just to add, I may be wrong. And I would love if you can tell me how and why I am wrong (and perhaps provide a link to something that explains the detail on the why department, I read through a few f,t stop/value related articles before and just now but they seem to be only about exposure calculations). But indeed they shine a new light on some areas that I don't previously know. And hopefully my original article didn't sound cocky because I didn't meant it to be. Thank you.

 

[catchlights]

Hey guys I would like to know what Are the differences when you use a normal zoom lens like 55-200 4-5.6 and zoom to 85mm and if you just use the 85mm 1.8g prime lens to shoot portrait? Other than it being a faster lens and have nicer bokeh, or subject isolation, is there anything else? Thanks

one very important issue you have not consider is you will spend lots of time on thinking of what is the best lens for taking portrait, and spending very little time to think how to create better portrait.

 

[CorneliusK]

one very important issue you have not consider is you will spend lots of time on thinking of what is the best lens for taking portrait, and spending very little time to think how to create better portrait.

Well said.

 

[Blur Shadow]

Ah, I am sorry that I forgot to elaborate on some constants.

1. Less glass (providing they are of similar quality) means less light dispersion due to refraction, so in my opinion (not 100% due to lens design and many other factors) less glass means better IQ. And of course, there are a whole range of different types of glass that compensate for refraction or do other wonders which complicate the matter further.

2. Provided of similar quality, yes I believe they are cheaper. A 50mm 1.4 will almost always be cheaper than a zoom lens that can shoot at 50mm 1.4 unless their quality differs greatly.

3. Again, I forgot to state the fact that the zoom lens must be able to cover the range of the prime (which don't happen very often) and image quality shouldn't differ greatly. Prime is almost always smaller and lighter.

Hope that clears the air.

EDIT: And just to add, I may be wrong. And I would love if you can tell me how and why I am wrong (and perhaps provide a link to something that explains the detail on the why department, I read through a few f,t stop/value related articles before and just now but they seem to be only about exposure calculations). But indeed they shine a new light on some areas that I don't previously know. And hopefully my original article didn't sound cocky because I didn't meant it to be. Thank you.

Ah. There is no really contention from myself. I just wish to clear up any misunderstanding that may arise. I mean, I won't want a newbie to be shocked when he finds out that a 24mm f/1.4 prime costs more than the already much revered 24-70mm f/2.8 zoom lens. Or the fact that the 24mm is pretty large and heavy.

There are always exceptions - look at the amount of glass employed in the top range wide angle and telephoto primes over say the humble 50mm or 18-55mm kit lenses. But the primes mentioned in the former tend to be superior optically. I think optical design plays a far more significant role than the amount of glass used.

As for size, well, offhand, I can think of the Sigma 120-300mm f/2.8 zoom lens being smaller than the 300mm f/2.8 prime.

Nonetheless, what I mentioned above are exceptions. Your initial posts and subsequent clarifications are generally sound. My intentions were just to ensure that newbies are able to understand the difference.

 

[Daoyin]

For a newbie, this discussion may take a bit to digest..

 

[swhyge]

For a newbie, this discussion may take a bit to digest..

some guru wanabes may take longer.... as they need to unlearn first, and this is tougher than learning afresh.......

 

[NewbieInCS]

I am newbie, so not sure of the science behind it...but I think I can attest to the "green become greener, black become darker" type of effect, better contrast and colour of the better lens. When I was on a crop with kit lens, I always find myself increasing contrast, saturation and changing the tone to get what I want. Along the way, I got better lens and found myself having to do less adjustment to get what I want. In the later stage, I got a ff body and found many of the ooc shots to be good enough.