Cameras, Lenses and Limitations

Hangar Flying
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For many many years I have been photographing with my trusty Nikon D40. Being only 6mp I have been wanting to upgrade for a while now. I had the opportunity to upgrade to a Nikon D7500 a few months back and thats where the trouble started.

I am usually photographing aircraft so my go to lens for 14 years now has been a AFS Nikkor 70-300mm VR ED 4.5-5.6. bought when I didn’t really know much. It has worked flawlessly until now or so I thought. Immediately I noticed a lack of clarity in my photos, I was shocked, and started many experiments with no luck. I tried everything until in my research someone mentioned that this lens is known for losing clarity above 200mm. Turns out in my years of using the D40, I just never noticed the clarity issues likely due to the lack of megapixels, since the D7500 is 21mp. I tried not going past 200mm and its a world of difference.

The question is… (since I lack knowledge on many things when it comes to photography is how to over come this). How do I over come this, it seems when you read about various lenses everyone mentions that they have their limitations. Having a 300mm lens reduced to 200mm is frustrating. Now that I understand the limitations I can work around them but I am wondering if theres any way to reduce the limitations. I don’t want to buy a 400mm just to get 300mm.

If I’m not making sense ask me questions so I can further detail my thoughts here lol

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Can you elaborate on what you mean by that? Maybe even post an example?

Is it low contrast? Low resolution? Dull colors? Stray light? Etc …

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In short, I think that it’s a physics limitation of the optics and physical design, so difficult to overcome with software. Maybe AI enabled image manipulation tools might be able to, but I don’t have experience enough to recommend one.

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Lens tech has come a very long way in the last decade or so and back then entry level tele zooms have never had great picture quality in either in the long end or short end. Your D40 is from a time were even top of the line professional cameras barely exceeded 15MP and you wouldn’t pair them with an entry level zoom lens.

A few options: spend a litle more money to buy a used professional grade tele zoom, spend money on a modern zoom lens that is intended to work with high MP cameras (can be entry level as long as it’s a modern design) or simply deal with it.

Edit: this is the kind of quality you can expect from a modern professional tele zoom. Tack sharp through its entire zoom range, even wide open, same goes for entry level lenses, they’re just lower aperture usually and lack other features:
Imgur

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Perfect example is the moon last night.

moongifopti

DSC_16033_300mm
DSC_16033_300mm1866×1856 154 KB

DSC_1603_230mm
DSC_1603_230mm1866×1856 155 KB

A notable difference in clarity.

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Thats what I was really hoping for, over the years I had gotten some great shots out of the D40 but I suspect your right in that its a incapability with the older lens.

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One last ditch effort: Is that the result of the autofocus? Did you already try to manually focus in couple small steps and review the results for best sharpness?

AF can be systematically off target.

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I have mucked about a little with that and to no luck so far. I’ve tried the AF fine tune as well and that made it all much worse lol

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I’ve had the same experience with my entry level 70-300mm zoom when I bought a new camera in 2018. Shortly after I managed to score a used EF70-200mm F2.8L IS II USM for 1000€ and IQ was way better at 200mm cropped to the same zoom level as a 300mm. I still use the 70-200mm on a 45MP body today. Good glass is something that’s gonna last a long time.

Definitely try manual zoom as suggested by @Poneybirds and you can also try and close the aperture to something like F8 but I wouldn’t expect wonders.

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Well any suggestions on what to look at for a future lens? It seems there are two different 70-300mm Nikon lenses one being well loved and one being mine, but I have trouble differentiating them. I see people mentioning the Tameron 100-400mm as an interesting option :thinking:

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The Tamron 100-400 and the Sigma 100-400 contemporary are both very decent lenses. I have had the chance to try the Canon version of the sigma lens a few years ago and was pretty impressed with it. It’s a little more expensive ( not that much though) but I don’t know how it compares and whether the lens is worth the 100 extra bucks.

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Another last ditch attempt to get your existing lens usable while you save for another: try shooting at f/8 or f/11 in Aperture priority (A) or Manual (M) mode (whichever you’re comfortable with, A will choose the shutter speed for you).

I’ve always found I needed f/11 and usually a gentle ND filter to get the props blurred nicely on propeller driven aircraft, so that might be a bonus?

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What device do you and others normally view your photos on?

I’ll be honest, on my phone and my laptop I can’t tell a difference between the 230 and 300 pictures. At full resolution on laptop the difference between the two is noticeable, but normally what I would ascribe to high ISO or a bit un-sharpening to hide pixel noise. It doesn’t scream “out of focus” to me.

If you’re not showing your images to people at 100% size on monitors, I really wouldn’t worry about it too much. On the average phone, tablet, or laptop screen the softness won’t be noticed by many. For portrait work, most people will appreciate it.

If you really want to see where the sharpness falls off, you’ll need to spend some time testing. It’s similar to the ISO testing I mentioned here: Photography Gear: The Camera & Lenses Thread - Hangar Flying - Mudspike Forums.

Find a good well-defined target with plenty of contrast for the autofocus (or something you can easily focus if you’re pulling focus manually), and plenty of detail to show a fall off in sharpness. Setup on a tripod, use a remote shutter release, and shoot with mirror lockup to minimize any camera shake.

You can do the quick version or the long version.

Quick version - Pick a medium aperture setting like f/11 or f/16 (usually these will produce the cleanest images, but not always). Start taking pictures from one end of the focal range to the other in about 25mm increments. Once you find out where you see softness, go back and go it in 5 or 10mm (whatever is the smallest adjustment you can repeatedly make). Then just like in the ISO test I linked above, show someone else your pictures on whatever you expect people to be viewing your work on, and don’t tell them what to look for or when. Ask them to find when “the difference starts.”

Long version - Start out at your widest aperture and shortest focal length. Make a grid for apertures and focal lengths, I recommend 1/2 stops if your camera will let you, or whole stops if not, and 25mm increments on focal length. Shot the grid. The aim here is to find your best settings, as the aperture at either end of the spectrum usually is soft and can have aberrations. You’ll probably find an area on the grid that looks pretty good (say f/11-f18 and 175-225mm). Take those boundaries and setup another grid in 1/3rd stops and 5-10mm focal length shifts, shot that grid. You’ll find the true sweet spot of a lens this way. If you really want to be thorough, now do the ISO test with your best aperture and focal length settings.

Both versions are fairly quick to shoot. Going through all the pictures can take quite a while, but it’s something you can do from the comfort of your couch or office chair.

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Exactly as jenrick says - but if you’re doing the quick version on a D7500 I’d use f/8 (Nerdy explanatory note: the high pixel density reduces the diffraction limited aperture, focal-iq.com estimates f/6.8 so improvements in quality due to the lens above f/8 will probably be lost in the increased diffraction above f/8 in the camera body).

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Can you really not notice the difference? I can see a clear difference in detail, even on my phone.

My own experience with these old entry level tele zooms is that they are not really suitable for modern cameras. It can get pretty frustrating when you try to get clear pictures especially when you want to crop in for the final image. Stopping down usually helps somewhat but it’s not gonna fix the underlying issue which is that these lenses were never designed for cameras with more than 5-10MP and even back then they were not the best in IQ.

A modern entry level tele zoom will blow these old lenses out of the water in terms of overall image quality (sharpness, colours, contrast).

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Nope, not until I clicked on them. As I said, if I wasn’t aware that I was supposed to be looking at the sharpness of focus, I’d have assumed the difference between the two was either a dithering issue or unsharpening.

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Interesting, I didn’t even have to try. I noticed the issue immediately.

Edit: Just had the chance to look at it on a monitor - yeah it’s rough. This is really the best case for the 300mm picture. It should offer slightly better detail and sharpness but instead it looks considerably worse than the picture taken at 230mm. That’s disappointing and if you print the image it will show.

Basically the lens is unusable at 300mm on this body as IQ is considerably worse, even in a comparison that massively favours the 300mm image.

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Hence my disappointment and frustration. Shooting aircraft mostly I often am at the furthest reach of the zoom since I can’t always be near a runway or whatever I’m looking at.

Luckily the 230mm is still a decent zoom until I get something to replace it.

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