Techniques, Reviews and Commentary
NEX 5n with Nikon 35-70 zoom
14/07/12Over the next few months I will be posting impressions of how it works with certain lenses and responds to tweaks and accessories, but for this post I’m going to present some insight into a lens that is really quite “left field” as far as NEX options go.....the Nikon 35-70 3.5-4.5 Ai.
Just to let you know the list of lenses I will be looking at include:
Olympus 24mm f2.8
Olympus 28MM f3.5
Olympus 100MM f2.8
Nikon 55mm 2.8 Micro
Nikon 50mm f1.8
Sigma 19mm f2.8
Sigma 30mm f2.8
And also a number of Minolta A series lenses, I just haven’t decided which ones yet
Before starting I need to point out that I never ever test jpegs, I shoot raw almost exclusively and only use jpegs for class demos or on my iPhone where I have no choice. Secondly I judge a lens on how the images look post editing (see separate article). I realize that might be a little controversial but to me the “out of camera” (OOC) look is irrelevant, what is more significant is how will the images look in a final state that represents what I would do with my normal workflow.
Ultimately this means what I normally get out of lens will likely exceed what average consumers get from jpegs and is not representative of what even RAW shooters may see if they just use “down and dirty processes” but nonetheless the attributes of a good lens shine through and are quite obvious. In fact, and I stand firmly by this, it is pretty easy to sort the wheat from the chaff as far as lenses go just by looking at the cameras review image and often even just the preview image, it’s just the fine nuances that are not totally obvious at shooting time.
This Nikon 35-70 lens is of course manual focus but using manual focus lenses on the NEX 5N is an absolute hoot. The touch to zoom in view, bright screen, auto exposure options and focus peaking make it both quick and easy, I reckon those blokes raving about Leicas M9s have a few lessons to learn when it comes to really good manual focus options.
And before we leave the manual focus, here is the really neat part, this is all done at the shooting aperture, which means....wait for it....you can see the exact effect of the DOF for the aperture you have chosen! If you don’t think that is important well clearly you have not drunk enough developer and fixer, good lord back in the film days we would have killed to be able to do that without having to contend with a screen that looked like a dark moonless night in winter.
This lens found its way onto my little Nexy as a happy accident, I had read on Ken Rockwells’ site that the 35-70 3.5-4.5 was one of Nikons ten worst lenses, well perhaps Ken got a bad one, or perhaps he didn’t even try it out, he does claim he makes stuff up after all. Anyway I trusted Kens’ opinion on the lens and expected nothing much, in fact I was just curious to see how crook it actually was and since I was given the lens for nothing what did I have to loose.
Dear old Ken made one valid point that I agree with, yes, the lens is plastic barreled and the attendant bits are plastic, but the mount (and internals I think) are metal. It doesn’t have quite that traditional solid Nikkor feel, it’s not the sort of lens to get excited about by just looking at it and holding it in your hand, a Zeiss it is not. However when mounted on the NEX 5N the balance is actually really nice and using a heavier lens is not the way I would want to go from an ergonomics perspective when using the NEX cameras.
Despite being significantly plastic (and lets be honest how many modern lenses are not) everything is solid and there is no slop to be found in focus, apertures rings or the zoom control.
I made a couple of shots out my front door on one of Goulburns more miserable days, flat light, flat grey sky and flat out cold, and then loaded the pics onto “Mac the Master of the Pixel” and cracked them opened in Raw Developer, my “go to” application when I really want to see if a Raw file is going cut like mustard or mush out like melted ice cream.
At first all looked a bit sad, low in contrast and weak in colour, but a little adjustment and sharpening with RDs super duper algorithms and these files were showing incredible potential at the 35mm focal length.
My curiosity suitably piqued I decided to give the little “worst Nikon lens ever” the benefit of doubt and shoot some stuff at all focal lengths on a better day, ie one with some sun, colour and warmth.
A few grabbed shots at the end of lunch whilst running a class in Bowral gave me what I needed to make some better judgments. The shots were taken at 35mm, 50mm and 70mm wide open and at f8, but hand held.
By 7.30 that night I was sitting at my computer trying to lift my jaw off the keyboard, these files were utterly sharp edge to edge, even wide open they were good. The files still had a low contrast “film like” look and the colour was subtle so they may not win over the MTV photographic crowd who like their colour “turned up to 11” but that filmic look really floats my digital boat and such files are a dream to post edit.
Now a few shots does not make a lens test, we need something more rigorous than that, just don’t expect me to shoot test charts etc, as far as I am concerned the only way to judge a lens is shoot real world pics and that is exactly what I did here.
These 3 photos below are at 70mm f5.6 full frame and then centre and corner of the frame at 100 % view
This next set is a 35mm full frame and the centre and corner of the frame at 5.6 at 100% view.
The next set of images were taken at my standard “camera test range” Marsden Weir, which is just a short walk from home and the office. In this case shots were taken at 35mm, 50mm and 70mm, at third f stop increments from wide open through to f9. The focus was on the same point in each shot and fine tuned for each image at shooting apertures to eliminate focus shift when stopping down and variability of focus with focal length changes. Incidentally this is not a true zoom, it does shift focus significantly as the focal length is changed. Naturally a tripod was used and the self timer was enlisted for triggering purposes, electronic first curtain shutter option enabled, 100 ISO and RAW used of course. In other words everything was optimal if there was a problem it was going to be the lens, not the set-up. At the same time I tested the kit zoom for comparison purposes.
Taken at 35mm wide open f3.5 right far corner, centre and full image.
Ah the kit zoom, look it’s not without its charms and I will deal with that little silver beasty another time, but lets just say for those who are asking/wondering....not even in the hunt, hell actually it hasn’t even mounted the horse.
Back to the “worst Nikon lens ever.”..
The NEX 5N has a very weak alaising filter and can be made to alias if the RAW extraction program is capable of really getting pixel level detail out of the file and “IF” the lens used is really really sharp. Nikons worst ever lens easily gets that NEX sensor alaising on patterns and man made objects with repeating structures. So much so that for the first time I found myself cutting the sharpening tool right back and turning on the “early stage noise reduction” in Raw Developer to control it.
Here we have a lens that actually resolves down to a pixel level on the NEX 5N in the central portion and is very close to the same right out to the far corners, regardless of focal length. In fact having conducted tests throughout the aperture range at each focal length I am confident in saying this it is actually a diffraction limited lens, in other words once you exceed the diffraction limits at around 5.6-7.1 depending upon focal length it gets noticeably softer in terms of resolution. Generally it is sharpest at f5 and that is pretty amazing for a zoom! Think about it, at f5.6 the kit zoom set at 50mm can hardly even resolve any edge detail and it’s barely any better at 35mm, yet this little beasty is peaking at an extremely high level. As an aside, (and I need to do another set of tests to confirm this for sure), it appears to out-resolve the minolta f3.5 55mm macro, and trust me its no slouch and is easily the best 50mm lens I have ever tried in the Minolta/Sony system and I have indeed tried them all, yes, that includes the f2.8 macro, f1.7 and f1.4 primes! This lens could I suspect easily make the most of the NEX 7s difficult sensor!
Ah but I can tell you something else as a tease, the Nikon 55mm f2.8 micro is even better than this little baby...more on that in another post.
So the 35-70 is sharp but what about its other characteristic, after all there is far more to lens performance than sharpness alone.
The lens is a very low contrast optic, in fact you can easily see this when looking at the histograms of images even shot under bright contrasty lighting, in other words the histograms don’t push into the extremes in the highlights or shadows, which as said makes for flattish images but we can always add contrast (especially if the exposure is taken with this in mind and the sensor is of the low noise variety) but taking contrast away from punchy image is much less satisfactory and often impossible. The highlights have a little creamy glow to them which is hard to describe but rather nice.
The colour rendition is somewhat warm with understated cyans and blues, in some ways a bit like old school Minolta glass but without that knockout colour punch those old A series lens exhibit. Shadows tend to neutral or warm which is nice, I hate cold shadows!
Bokeh? Honestly not really that great, it looks a bit busy to me and I wouldn’t be choosing this lens if I were shooting a portrait or some other image where smooth defocused areas were needed.
Geometric distortion, I am not sure really, I have not deliberately gone out and shot stuff to show any issues up and rarely does it ever bother me unless shooting architectural images for money. I can say however that I have not seen any issue at all in any of the regular shots I have taken other than some barrel distortion with front on shots of buildings at 35mm but it should be noted this was very easily fixed.
Vignetting, there could be some but generally with zooms in this range designed for full frame and working with moderate maximum apertures it is quite rare to encounter any issues. I can say however that compared to the kit lens it is obvious this one has no vignetting issues worth worrying about unless perhaps you like shooting white walls at close range for fun!
What about field curvature? At moderate distances this seems to be a moderately flat field lens, no significant nasties at all, the focus holding basically across the hold image at the intended plane of focus.
The field curvature is virtually flat at 60 and 70 mm regardless of focused distance but the 35-50 range are shows significant field curvature as you attempt to focus on infinity objects. Basically the curvature bends back towards you at the edges and corners, this is tricky to deal with if you are unaware of what is going on. When you focus the at infinity in the centre of the frame the edges of the horizon will be blurry (though I have seen far worse) whilst the corners closest to you will likely be quite sharp.
The type of field curvature I have described can be useful as a creative tool and is definitely easier to work with that the opposite type, where you focus on near object in the centre of the frame and then find the rearward corners of the frame are sharp but the near corners are blurry.
Ultimately to get landscape shots that are sharp throughout the entire frame you need to focus at infinity distance objects about a 1/3 to 1/2 way out from the horizon centre and use an aperture of f6.3-7.1. Do this at 35-42 and 50mm and suddenly everything looks incredibly sharp. I expect it is this behavior that has led people to conclude this is a soft lens, it isn’t just misunderstood.
As said the 60 and 70mm focal lengths are virtually flat field so you just focus on the plane you want to use for peak sharpness.
The 50mm field curvature can be very useful as when you focus on the centre of the frame for say a portrait, so long as you have no near objects showing in the corner of your frame it will give a far more shallow DOF effect than you would expect based on the f stop chosen. It also means that the 35mm setting can give a rather shallow DOF effect that seems to be rather more akin to what you would expect from a lens shooting at say f2.4 or so.
And now the biggy, the one that really gets on my digital goat, “chromatic aberration”. Few prime lenses and even fewer zooms are what I would call CA benign, in other words have so little CA that it is not worth fussing over. Normally you can correct it in the editing applications so it does not show up in the final print, but (and dear reader this is the bit most folk don’t really account for) usually a lens with significant CA is far less sharp to the edges and corners cause basically the offending colour channels are not focused properly at the sensor plane. Fixing the CA will not regain the clarity in the offending channels though it will cure the fringing issue, so obviously if you want peak sharpness all CA is a NO NO!
This “worst of all NIKONs” has absolutely no sign of CA at anything approaching sensible levels of magnification, in fact to find any and thus correct it I had to view the image at 300%! Seriously, I am going on record as saying this lens has the least CA of any lens I have tested on this camera and is line ball with the best I have ever tested on any camera.
The one failing of this lens is flare, actually there are more flares than a mid 70s disco if you point it in the wrong direction and its not a nice type of flare either, sort of looks bluish and mushy to me. Yes this baby needs a really good lens hood, because bright lights even at angles right out to the side of the lens can cause it to glow like a neon sign
Many argue that 35-70 is a stupid focal length for APSC formats but I disagree, or perhaps my needs are different to others. 35-70mm covers the old 50-105 focal length and I find that very useful, in fact if you gave me a 24mm lens and a 35-70mm zoom I reckon I could cover about 90% of my personal shooting needs.
Ultimately this is not an easy lens to use, images will need some levels and curves tweaking, the colour saturation will not knock your socks off out of the box and the field curvature needs to be accommodated if you want to get all over sharpness for landscapes etc. But I will say this, compared to the kit lens at 35 to 55mm this lens eats it up and spits it out and of course you still have 70mm as a very nice performing option.
Unlike the kit lens this one can actually be shot wide open and still perform quite well and of course even at 50mm it is still and f4 lens rather than f5.6. So we have no OSS but then in the real world this lens needs 2 stops less on the aperture to give sharp images so much of the OSS advantage is negated!
Of course it is not a replacement for the kit lens, it is a 35-70 after all, but in so many photographic instances it would be a vastly better choice.
Oddly for a zoom it worst performance seems to be bang smack in the middle of the focal length range with peak performance at the very extremes, odd indeed and no I cannot explain why.
Now promise me this, say after me now “I will not go out and bid the price of this lens up on eBay and promise to keep this all a big secret”.
That way I can go out and corner the market on cheap “worlds worst Nikon lenses” so when the world wakes up to this little jewel I can get rich quick!
Whats that? You’re going to break your promise, I wish I would learn to keep a secret.