Prime Lens vs VR

[Philuk1]

I went through an interesting experimentation recently.

I own both a Nikon 50mm 1.8D prime lens (PL) and a kit lens 18-105mm. Beyond the fantastic DoP capacity of the PL, I really wanted to test the actual IQ compare to a much inferior kit lens as a standard aperture, let's say f/8. All parameters being equal, I took my neighbour's wall from my window before checking the result on my laptop screen.

Well conclusion is pretty surprising, despite a fast enough shutter of 1/50, the PL produced a more blurry results than ths stabilised lens. Bricks edge are just better defined with the cheap VR zoom. On the other hand, the PL is clearly producing a much lighter picture, which would probably be useful in low light condition.

So what is the point of a PL? Obvisouly I would need a tripod to get sharp pics with it in anything but a sunshine day, which cancel out the benefit of its low light capacity as even my 18-105 could get a good shot on a tripod in near pitch dark condition.:bonk:

My friend stopped using its prime as he got blurred result far too often. So is it down to strict discipline to get anything out of a prime or I just don't know how to use it?

 

[redddraggon]

The 50mm will work better at F/1.8 that your kit lens will. Your kit lens also has VR, so when using a slow shutter speed of 1/50 it should give a sharper image than the 50mm.

These days zooms are good, but they tend to be slow, F/2.8 and slower, and that's where the prime comes in.

Assuming I nail focus I get sharp results out of my primes, I make sure I'm at the right aperture and shutter speed for the job.

 

[gad-westy]

1/50mm is very slow to handhold a 50mm on a crop body. I would be looking for more like 1/125.

You may also have gone beyond the sweet spot of the prime lens but were probably more or less bang in the middle of sweet spot for the VR lens. Typically this will be 2-3 stops from wide open.

Lastly, any idea why the prime's image was lighter? If all things were equal, you'd expect the exposure to be the same.

 

[gad-westy]

Just to add to that last post, there are also things that your prime can do much better than your kit lens. One is shallow depth of field shots. The other is that by using a wide aperture, you can use a faster shutter speed, which means you might have a chance of freezing motion on a moving subject. Good though Vr systems are, they cannot account for subject movement.

Your test does play onto the hands of vr lens to a large extent.

 

[Martyn...]

Lastly, any idea why the prime's image was lighter? If all things were equal, you'd expect the exposure to be the same.

I wouldn't, especially if the zoom has more elements ... less light is actually transmitted through the zoom to the sensor, "T" stops more often used in the film industry take into account light lost absorbed by the glass and reflected back, so the more elements the fewer photons that get through.

I did an experiment using my 200-400f4 zoom (@300mm), and my 300 f4 prime, the difference was around 2/3rds of a stop.

 

[gad-westy]

I wouldn't, especially if the zoom has more elements ... less light is actually transmitted through the zoom to the sensor, "T" stops more often used in the film industry take into account light lost absorbed by the glass and reflected back, so the more elements the fewer photons that get through.

I did an experiment using my 200-400f4 zoom (@300mm), and my 300 f4 prime, the difference was around 2/3rds of a stop.

I really just wanted to check that nothing else had been altered between tests but this is good info all the same.

 

[simonkit]

Modern zooms have improved greatly although comparing lenses at F8 won't really demonstrate the difference as it's the "sweetspot" of most - comparing at f2.8 is likely to show greater differences in sharpness. Having said that IQ isn't just about sharpness, it's also about colour & contrast rendition and primes often perform better in this respect.

I use both zooms and primes and rarely see any sharpness differences as I shoot mainly at F11/F16,

Simon

 

[Martyn...]

I really just wanted to check that nothing else had been altered between tests but this is good info all the same.

It is logical, but in all honesty not something I had thought about until a few years ago, someone on here asked for users to do a few simple tests and let them have the results, I had assumed they would be the same, but once I had done the test and considered the results it was obvious.

To the OP I have the 50mm f1.8, if used correctly it is going to be sharper than the kit lens, it is one of my sharpest lenses, as stated above you want to be at around f5.6 and 1/100 sec to get a fair representation of its ability.

It is just a case of practice and understanding how your kit works to give the best results, the VR kit lens is probably a little more forgiving in this respect.

 

[badboy1984]

i think the test should done it on the tripod to see the optic difference. The test seems abit unfair consider both using the same setting but the zoom have VR to eliminate the hand shake where as the prime still using a slow shutter speed.

Depend what the OP want to prove, if wanted to prove the VR give better optic handheld using slow shutter then yeah the zoom with VR beats the prime with slow shutter.

but for optic i would say pop it on the tripod and test it again.

 

[SnappyHappy]

My new 35mm prime (and the older 50mm prime), produce more 'contrasty' images than the standard 18-55 kit lens. I think contrast plays a big role in how you (and others) define IQ. Just my opinion
Less glass involved as well.
I've only got experience of Nikon (and i'm no expert), but to my eyes there really is a noticeable difference between putting the kit at f5 and the 35mm at f5, for example....

Just last night, I was handholding the 35mm at 1.8 in a pretty dark room with a lamp on in the far corner taking pics of my youngest. This produced shutter speeds of 1/30 and they were acceptable, not prize winners. Wouldn't have even attempted this using the kit lens - OK, the IS0 was around 600, but on my D3000 IS0 isn't acceptable above 800 IMO But for me, 1/30 handheld was OK.

I'll see if I can put an example up (dont have anything showing the kit lens though)

 

[SnappyHappy]

Here's one from the 35mm last night at 1.8. The pic is a long way from perfect (damn!) , but just showing you an example of a moving object (baby) in a dim room with 1 lamp in a faraway corner.
This would have been taken at ~1/30 i reckon and about 5 or 600 ISO (my camera is set to never go above 800).

This would not have been possible with the kit lens, by a long way, and it almost worked, not quite:shake:, but i'll probably keep it anyway.

 

[SnappyHappy]

...I should add, I dont want to cause confusion by implying that the VR would have helpd you with a moving object either

 

[badboy1984]

...I should add, I dont want to cause confusion by implying that the VR would have helpd you with a moving object either

You moving object as in motion? VR doesn't stop motion, it only reduce handshake/camera shake.

 

[SnappyHappy]

Badboy, yeah, that's what I mean, I kind of made it sound like I was implying VR would help with the moving object:bonk:
(VR wouldn't have helped that pic I posted), a faster shutter speed would have but I was at my limit with what was available....
For me with the 1.8, dim room and 1/30 or 1/60 can work a lot of the time depending on baby speed but yes, that pic is soft because of shutter speed, not lack of VR (unfortunately)

 

[Philuk1]

Thanks for the reply so far, so to sum up, everyone agree that a prime will be more effective on:

-Bokeh effect (obviously)
-Moving subject (especially in low light) as VR doesn't help in this situation
-Likely to be sharper £ for £ ish on a Tripod than a zoom lens

i think the test should done it on the tripod to see the optic difference. The test seems abit unfair consider both using the same setting but the zoom have VR to eliminate the hand shake where as the prime still using a slow shutter speed.

Depend what the OP want to prove, if wanted to prove the VR give better optic handheld using slow shutter then yeah the zoom with VR beats the prime with slow shutter.

but for optic i would say pop it on the tripod and test it again.

Losing the ability to zoom is quite constraining so it really is essential for me to understand the actual benefits of a prime over a zoom beyond the obvious bokeh effect. So far, other than the three points mentioned above, it is difficult to justify using a prime for let's say Landscape or Architecture where it is not always possible to move back or forth to frame. Some say the contrast are better, if anyone can confirm their feeling on that?

I take a majority of my shots handheld, should I understand that prime are not so great for that use ?:shrug:

 

[redddraggon]

I take a majority of my shots handheld, should I understand that prime are not so great for that use ?:shrug:

Primes are better for shooting handheld as you can use a bigger aperture and get a fast shutter speed.

You're clearly not using a prime to it's advantage by stopping it down to F/8 and trying to shoot held at a slow shutter speed.

 

[gad-westy]

I take a majority of my shots handheld, should I understand that prime are not so great for that use ?:shrug:

Quite hard to generalise with this as there are huge ranges of both primes and zooms. There are fast zooms that are as fast as some primes. There are primes with VR...

Your comparison above shows more the benefits of VR rather than any difference between a prime and a zoom. If you'd turned VR off on the zoom, you'd have been doing a like for like comparison but realistically your shutter speed would be too slow to get consistent results.

The reason people suggested using a tripod in your test is to eliminate the human factor and get a true idea of what each lens is capable of.

 

[CyBeRkId2002]

Alternatively, and I really don't want to sound harsh about this, but get out and use it rather than shooting walls. Once in use the advantages listed above (DoF, Colour Rendition - a biggie for me, low-light ability, less arm ache) should be immediately obvious. If not perhaps your ability isn't getting the best out of the lens but I am sure over time the differences will become apparent. If not then perhaps primes are not for you - they aren't for everyone - and sticking with kit lens or alternative zoom may be best.

 

[antihero]

Thanks for the reply so far, so to sum up, everyone agree that a prime will be more effective on:

-Likely to be sharper £ for £ ish on a Tripod than a zoom lens

I take a majority of my shots handheld, should I understand that prime are not so great for that use ?:shrug:

I wouldn't say that's entirely true. The inherent sharpness of the actual lens determines it's sharpness on a tripod. A lens should be sharp on a tripod no matter if it's a zoom or prime, dependent on how sharp the lens is in the first place!!!

A prime should be more than sharp handheld as long as your exposure is adequate enough.

If you have wobbly hands, you are bound to get better results at 1/50 with a VR lens than a non VR. You need to be shooting at 1/80 minimum really (focal length of lens including crop factor).

A lot of people are quick to criticise large aperture glass through lack of technique rather than an issue with the lens. The DoF of a 1.8 is pretty narrow, so without correct technique it is easy to get OOF shots and then blame the lens.

Practise, practise, practise is the key. Once you get the hang of using the 50mm 1.8 you'll love it. A nifty fifty is pound for pound probably the best lens anyone can buy, regardless of system.

A prime does have zoom ability, it's known as legs!!! You do have a valid point though in saying a zoom can be more than advantagous when shooting landscapes or architecture.

This is shot at f1.4 on a moving target;

Mud! by dobinio, on Flickr

 

[squishy]

Plus one to the above. Spot on advice.

 

[Philuk1]

I am not going to pick up every comments, but there are definitely some great inputs in this thread.

I guess that having mostly shot with a very forgiving VR zoom, I probably overlooked the amount of pure technique required on "sharper" lenses. I ll definitely play around a bit more with the 50mm to get the essence of clean focus and DoP in photography.

Great pics Paul by the way.