Poor Blue Skies with Nikon 24mm f/2.8 AiS MF Lens

<p>When I use my Nikon 24mm f/2.8 AiS MF Lens for landscape or travel photos that include rich cerulean blue skies, the skies are rendered poorly in the resulting image. I first noticed this two years ago while shooting the Potala Palace in Lhasa, Tibet. At the time, I wrote it off to an expired roll of Chinese film I had purchased. More recently, I noticed the same phenomenon when shooting a building for a client with my Nikon D800. I shot first with my 24mm lens, then switched to my Nikon 28mm f.3.5 PCE lens. The differences in sky color were striking. The latter rendered the perfectly blue sky as I saw it. The 24mm lens rendered the sky a washed-out, almost turquoise color. Unfortunately, I discarded the bad 24mm image. However, I decided to shoot some test photos with every lens I had in my collection. The 24mm's sky color wasn't as bad as earlier, but it was still a bit faded compared to what I perceived the color of the sky to be and it certainly differed from what several of my other lenses were rendering. <br>

Is what I've experienced typical with the Nikon 24mm f/2.8 AiS MF lens? Am I misusing it in some way? Do I have a bad copy that I should replace? I bought the lens brand new. <br>

Thanks in advance for any help.<br>

--Greg Embree<br>

<br /><img src="http://home.comcast.net/~suza1/Potala%20Palace.jpg" alt="" width="500" height="258" /><img src="http://home.comcast.net/~suza1/4_DSC_0283.JPG" alt="" width="500" height="334" /><img src="http://home.comcast.net/~suza1/2a_DSC_0281.JPG" alt="" width="500" height="334" /></p>

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<p>Actually the 24mm image is overall a bit brighter than the one from the 28-105, a good reason for the sky to look different, as well as the road.</p>

 

<p>I agree that the 24mm shot looks like it had a little more exposure than the zoom image. How old is the lens? Is it possible that the aperture blades are a little sticky and are not closing to the correct setting quickly enough?</p>

<p>The exposure does appear to be slightly different between the two images. Shoot both in manual exposure mode, same aperture and shutter speed, on a tripod so your framing doesn't change, and see if the two are closer.</p>

<p>Does the 24mm have a hood? Stray light from the side could be reducing the overall contrast if there's no hood.</p>

<p>Beyond that, I dunno. I don't have any experience with the 24mm AiS, but I did have the 28-105 for awhile and I know it was a good, contrasty lens. Some lenses just have less contrast than others, and maybe the 24mm AiS is one of them?</p>

 

<p>I do not have the 28-105 or a D800.... but using an Ai 24mm f/2.8 on a D700 and D300. I have no specific problems with this lens (I like it very well on the D700). Indeed the exposure between the 2 images looks subtly different, explaining part of what you might see.<br>

In general, though, I do find my older lenses are quite a lot less contrasty and less satured than newer lenses. They have a subtly different look (in my view, the older lenses do yield better when converted to B&W than modern lenses do, but the modern lenses have more presence and vividness for colour work).</p>

<p>The difference in exposure is probably no more than 1/3rd of a stop, which is within the accepted spec for aperture accuracy. Plus the wider angle is going to affect the camera metering. IMHO there doesn't appear to be much wrong with the lens by way of contrast. There's a slight chance that the change of sky colour just might be due to the UV or IR transmission characteristics of the 24mm lens. It's got a lot less glass in it than a modern zoom.</p>

<p>To see if the aperture is sticky, take a series of exposures in <em>manual</em> mode from wide open to f/16 while adjusting the shutter to keep the same exposure. If the shots get brighter as you stop down, then suspect a sticky aperture, but don't confuse the inevitable variation in vignetting with a change in exposure. You need to look at the exposure in centre frame only.</p>

<p>Thanks to all for your observations and suggestions. The lens is two years old. I just now went back to my EXIF data for the two test shots. I took both pictures in aperture-priority mode at f8 and ISO 1600, with no lens hood or filter. The camera metered the shot taken with the 28-105mm lens at 1/4000 and the 24mm lens's photo at 1/2500. I never realized that a wider-angle lens would cause the camera to meter differently. (I learned something!) The next time we have a rich blue sky here in Arlington, Virginia, USA, I'll do the tripod tests suggested by Jeff and Rodeo Joe. </p>

<p>Greg, note with 'older' lenses I mean older designs. Your AiS lens might be 2 years old, but its design is essentially a ~1977 lens.</p>

<p>The exposure difference is pretty small, maybe -1/6 EV, but there is also a colour shift. The zoom looks about +5cc Magenta. </p>

<p>If you're using using AWB, I'd guess it should 'correct' to the same WB assuming a similar colour make up of the scene.</p>

<p>If you're on one of the pre-sets, different lens coatings <em>do</em> change the final colour, or as Rodeo says, different filters, ie Skylight UV or plain protection would affect the final colour. If I put most of my UV filters on a piece of white paper they have a subtle magenta hue.</p>

<p>Greg. A new batch of Nikon older MF lenses do have the current SIC-coating, while older have NIC at most. There is a noticeable difference between the two lens coatings. According to a good resource http://www.photosynthesis.co.nz/nikon/ your zoom was made between Dec 98 - 2005, so it propably has the newer SIC coating.</p>

<p>ISO 1600?? f8 @ 1/4000?? Are you trying to freeze the motion of invisible speeding cars?<br>

Those seem pretty 'unusual' settings.</p>

<p>Were/are you using Spot, Centre-Weighted or Matrix? Unless the views are identical the meter is going to 'see' different proportions of bright & dark in the scene and adjust accordingly. Equally if Active D-Lighting is activated, it <em>might</em> adjust things variably too.</p>

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<p>Thanks to everyone for the additional insights. @Wouter, I knew you were referring to older designs. I was answering Dave Carroll's question. @Kari, your information about different lens coatings was all new to me. Thanks. @Mike: I was using matrix metering and AWB. The 1600 ISO setting was user carelessness. When I do my tripod tests, I'll try to be more alert. <br>

Question for everyone: I bought this lens for travel and daytime and nighttime cityscapes. I like operating with three prime lenses, and this 24mm was going to serve as my wide-angle. I'll perform the tripod tests suggested above, but if this lens doesn't render blue skies to my satisfaction when I'm on a trip and shooting away in Aperture Priority or Program mode and AWB, would I be better served by selling this lens and replacing it with a more modern version, such as the Nikon 24mm f/2.8D AF Nikkor Lens? I'm retired and am pursuing photography as a hobby. I get paid gigs once every blue moon, so the durability advantage of my manual focus 24mm is not essential. </p>

<p>The AF-D 24mm f/2.8 has the exact same optics as the AiS version, and since you have a very late AiS, with Kari's info in mind (learnt something too today!), there would not be a whole lot of difference. Except that the AF-D feels a lot cheaper ;-)</p>

<p>Hmm.<br>

Back in film days, the film tones usually were so prevalent that lens hue mattered little.<br>

In digital days, more depends on color balance.</p>

<p>Still, lenses were always said to be different colors, but when <em>Modern Photography</em> actually tested them years ago, I seem to recall that the "family" characteristics (X is warmer, Y is cooler) didn't seem very clear - more of an individual lens matter.</p>

<p>Here's your palace shot with "automatic color" in PS.</p><div></div>

<p>Wow! That's exactly what I recall having seen with my naked eye and what I had hoped to capture with my Nikon EM and 24mm lens. I'm going to dig up my original negative, rescan it, and use PhotoShop's magic button. I know it'll be a cliche image, but it'll be my cliche image. Thanks, JDM! </p>

<p>Or dial in -.3 or-.7 exposure correction in whatever program you use for post processing. It should recover the saturation you are after. When I compare the Zeiss 21mm f2.8 vs the Nikon 17-35 f2.8 the Zeiss is brighter by about 1/3 stop. Easy to adjust when I want to.</p>

<p>I'll experiment with that, Robert. Thanks. </p>

<p>With regard to "old" or new coatings. IMHO far too much value is placed on what coatings are used on a lens. IME, anything post-NIC is going to have about as good anti-reflection control and contrast as you can get, and I'd defy anyone to see the difference in the final image between NIC and SIC coatings. The lens complexity itself is far more relevant.</p>

<p>Below are two pictures; one taken with an MF 24mm f/2.8 Ai-S Nikkor (bought new ca 1982), and the other at 24mm with the 14-24mm AFS nano coated zoom-Nikkor. Which is which? Was it the top or was it the bottom? - D'you know, in all the excitement I can't rightly remember. But do ya feel lucky? .... well ..... do ya?</p>

<p>Actually I know very well which is which, but it's probably not the way round that you'll guess.</p><div></div>

<p>Interestingly the bottom shot (12-24mm?) looks about +1/6EV (relative), but I gotta say I can't see any colour shift. I'm guessing this is also why the upper is a tad more saturated.</p>

<p>Talking of nanobots, is that a decapitated Dalek lurking there under that bush?</p>

<p>Dalek? Maybe, but it now serves as my compost bin. It came complete with an ace sink plunger and a zapping thingy that comes in handy to scare off the neighbours' cats. How the mighty are fallen!</p>

<p>Incidentally, both lenses were shot manual with the same aperture and shutter setting, so any difference in exposure is either down to lens flare or the added vignetting on the MF lens ---- drat! Now I've probably given away a big clue as to which lens is which.<br>

The EXIF data is a red herring BTW. I realise now that I didn't change the non-cpu lens setting on the camera when I fitted the 24mm Nikkor. </p>

<p>Oh, you mean that the apertures you set on separate lenses (when using Manual) don't quite 'match' in light through-put terms?.... maybe it's a T-Stop difference (problem)? :-)</p>

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<p>The second "D800 24mm" image is overexposed, has blown blue channel. Blue can't go past 100%, while R and G may still rise... typical digital overexposure artifacts. <br>

The best cure is to watch the RGB histogram and adjust the EC wheel so that the hottest channel barely touches the right edge (ETTR). If shooting raw, you may expose about a stop higher and recover using the EC slider in the raw converter. This is what you want to do to get least noise.<br>

Second best, once you're already stuck with a blown image, is highlights recovery in software. Lightroom 4 and Raw Therapee 4 have automatic highlights recovery algorithms which detect such partially blown highlights and attempt to recover the blown channel based on luminosity info from the remaining channels. The outcome usually has less false colours, looks more like a blown image on film. <br>

It is not uncommon that the camera meters half a stop hotter with one lens compared to the other. Aperture calibration is not awfully precise. <br>

Grain comes from sensor noise. Particularly at high ISO (use base ISO if you have enough light) or due to underexposure. But even at base ISO, in dark blue skies the blue channel is around midtones, while R and G are very low, in the noisy region. Noise may be present elsewhere in the image too, but is most noticeable on featureless surfaces such as skies. It can be removed by selective filtering. </p>

<p>Thanks, Sem. It never occurred to me to monitor each color's histogram. I definitely will from now on when using this lens. </p>

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<p>I took both pictures in aperture-priority mode at f8 and ISO 1600</p>

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<p>The exif data says otherwise. The top image is f/8 @ 1/2500 and the bottom is f/8 @ 1/4000 according to the exif viewer plugin I'm using.</p>

<p>Henry Posner<br /><strong>B&H Photo-Video</strong></p>

<p> Errr Henry P....... I'm mystified...??<br>

<strong><em> </em></strong><br>

<strong><em>I took both pictures in aperture-priority mode at f8 and ISO 1600</em><em>, with no lens hood or filter. The camera metered the shot taken with the 28-105mm lens at 1/4000 and the 24mm lens's photo at 1/2500.</em></strong><br>

<strong><em> </em></strong><br>

That's what the OP said...(and what my EXIF viewer says too??)<br>

........what are you on about?? I'm obviously missing something??</p>

<p>ISO 1600 and f8 gives 2 different 'speeds'...... nothing new there!</p>