Focus Ring Stops vs Continuous

R

Rink

New member
Good afternoon, everyone.

I’m new on this forum, glad to be here, and I have a question about a lens.

I have a Nikon D5500 with a couple lenses. One is the AF-P 70-300mm which has a focus ring that turns continuously and never stops. I understand that there is a similar lens that has a focus ring that does have stops. I’ve read a bit about the differences in these focus rings, but I wouldn’t call myself knowledgeable on the subject.

I have trouble acquiring infinity focus manually with this lens (at night). I’m considering selling it and purchasing the model with focus ring stops if that might make it easier to find infinity focus. And I’m wondering if this continuous focus ring provides some other offsetting advantage for me compared to a focus ring with stops.

I’ve been into photography for many years, but I’m an amateur and photography is strictly a hobby for me. So I try to keep my expenses (and complication) as low as possible. I’d appreciate any advice on this situation from more experienced folk.

I hope this is an appropriate post and on the appropriate forum. If not, someone just please let me know.

Thx, rink.
 
BF Hammer

BF Hammer

Senior Member
Hard stop or no stop, it should not really make a difference in dialing in to infinity focus.

I cannot determine which version 70-300mm AF-P you have. There are 3 different versions listed at imaging-resource.com. I used to have one, it was a full-frame version. I was not impressed with it's optical qualities. Is it possible you are seeing a typical unsharp image for a lens that struggles in fine detail? The usual way to focus for astrophotography is to use LiveView and use the screen zoom to enlarge a star as much as you can, then adjust the focus ring until you make the star as small as possible. That will be infinity focus, but it does not assure that the lens can make that star sharp.
 
R

Rink

New member
Thanks, good points to consider. My thinking on the lens with stops is that at least I can only go so far before I know that I've hit infinity focus. With the continuous ring, I never know for sure. I have been using the live view, zoomed to max, focus as well as I can...and still getting blurry photos of the moon. Actually, the full moon is bright enough I could probably use autofocus.

The full marking on the lens is: AF-P NIKKOR 70-300mm 1:4.5-6.3G ED, it's also marked with DX and VR. Made in Thailand, serial 20954703.
 
Clovishound

Clovishound

Senior Member
Focusing on the moon, you should be able focus just fine in the viewfinder. If you are looking to expose the moon properly, rather than stars, there is plenty of light to be able to stop down to F11 give or take, which will give you enough depth of field to make up for any minor focusing error.

BTW, what are you using for exposure? You definitely don't want to be using autoexposure. For the moon you should start at F11 at 1/200 sec ISO 100. I would definitely put the camera in manual mode with manual ISO. Take a couple shots, look at them and adjust from there. You may have to give it a stop or two more. You should be able to see decent detail of moon craters. If you using autoexposure, it will grossly overexpose, trying to balance the scene between the bright moon and the black sky.

Here's one I took last year. I used my 200-500 on a full frame Nikon firmly attached to a tripod. It was shot at F11, 125th sec at ISO 200. Your 300mm on a crop frame sensor camera should give you an effective 450mm, not that much different from my 500mm. I did crop this image a good bit, but there was enough detail to sustain that.


_DAB2143.jpg



Here's one I shot using aperture exposure. 1/20 sec at F6.7 ISO 800. It is properly focused, but doesn't look very sharp due to over exposure. It is probably about 7 stops overexposed, if my math is correct.


_DAB2081.jpg
 
Dawg Pics

Dawg Pics

Senior Member
Fuzzy moon shots can be caused by poor atmospheric conditions as well. If you post an image, we can get a better idea of what is happening.
I find infinity focus difficult at night thanks to noise in the image and dim stars. Poor atmosphere doesn't help either. You might consider getting infinity during the day and then marking the lens with some gaffer tape.
I saw a recommendation to get a magnifier to use on the back screen to help see if the stars are in focus. I bought one, but I find it is kind of difficult to use, but helpful.

Are you using a tripod for moon shots?
 
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BF Hammer

BF Hammer

Senior Member
Zoomed in to 300mm, the earth is rotating pretty fast, plenty fast enough to to blur the moon. Consider 1/500 or 1/800 to be the shutter speed to use. F/8 would be fine for the aperture, so use the ISO to dial in exposure if you can't move the f-stop lower.

Clovis touches on it, but being overexposed on a full moon is very easy to do. Bring down that exposure and consider dialing it up in post. You cannot bring back detail that is blown-out in white. Also take note that those craters show much better if there is shadow. There is barely any shadow to see in a full moon. Get out in a partial phase and those shadows start to jump out near the terminator line.

I think this would be your lens, but there is no lab test or review done. So I cannot comment further on optical properties. https://www.imaging-resource.com/lenses/nikon/70-300mm-f4.5-6.3g-ed-dx-vr-af-p-nikkor/review/

And I know that the moon is a pretty easy astrophotography target. It really is how I dipped my toes into the subject. But it also has it's challenges that you need to learn to overcome. It's the same sort of solutions to apply to photographing nebulas or even planets. You can take 60 photos of the moon and stack them with freeware autostacking software. It works to blend out the sensor noise and give a virtual boost in pixel-density for the details. Under exposing with a fast shutter is the ideal way to do this stacking.

ps: On tripod, do not forget to turn off the VR of the lens. That blurs things also since VR is for handholding.
 
Marilynne

Marilynne

Administrator
Staff member
Super Mod
Dawg Pics said:
Unfortunately, we no longer have the EXIF data with a simple click. I used that information a lot when trying new things. Just looking at what people were using to get certain shots helped me a lot.
Click to expand...
CS, you can see the EXIF by putting your cursor on the bottom of the photo. Or do you need to see more information?
Screenshot (136).png
 
R

Rink

New member
Good afternoon.
Thanks, everyone for the suggestions. I’ll try some of these suggested settings and keep working on it.

My pics from recently were so bad, I deleted them. So I can’t show them or reference the EXIF data. I believe it was f11, about 1/250 sec, ISO 100.

I’ll try to attach here a photo from last year, f6.3, 1/200 sec, ISO 200. It’s ok, not great. Certainly not as much definition as in the Moon pic posted by clovishound above. I think I may have used autofocus on that one, after having trouble getting focus manually.

Typically, when shooting moon or stars, I use a tripod, turn off VR, use manual focus, and use manual mode exposure. I use the live view screen, zoomed all the way in to attempt focus, then secure the focus ring with some tape as mentioned by dawg pics above.

Thx, rink.

IMG_7375.jpeg
 
Marilynne

Marilynne

Administrator
Staff member
Super Mod
Rink said:
Good afternoon.
Thanks, everyone for the suggestions. I’ll try some of these suggested settings and keep working on it.

My pics from recently were so bad, I deleted them. So I can’t show them or reference the EXIF data. I believe it was f11, about 1/250 sec, ISO 100.

I’ll try to attach here a photo from last year, f6.3, 1/200 sec, ISO 200. It’s ok, not great. Certainly not as much definition as in the Moon pic posted by clovishound above. I think I may have used autofocus on that one, after having trouble getting focus manually.

Typically, when shooting moon or stars, I use a tripod, turn off VR, use manual focus, and use manual mode exposure. I use the live view screen, zoomed all the way in to attempt focus, then secure the focus ring with some tape as mentioned by dawg pics above.

Thx, rink.

View attachment 396053
Click to expand...
I see F/6.3, 1/200s, iso 200
 
BF Hammer

BF Hammer

Senior Member
I could show-off here using a lens not currently available to you and say it's easy, just yadda yadda yadda.

But I'll instead show what is possible using lesser gear. Last year I thought I would try out my infrared converted D600 (16MP sensor) with a very old 500mm Nikon reflex lens. Late 1970's vintage I presume and it is quite fuzzy today. Not what we consider sharp at all. I added an old 2x teleconverter just because this is the one lens I have that does not autofocus or meter and the teleconverter is a dumb type with no AI pins. So I am shooting 1000mm on a full frame body. But the teleconverter also reduced the f/8 down to f/11.

I did the trick of pre-focusing on a star by making it appear as small as I could. Moon is underexposed, and yes I shot at 1/200 which is too slow. But I also was using a star-tracker mount so I hoped for an assist there. I also took 20 photos with the intention to stack them. Here is the last single image of the run.
20220214_29.JPG


And using SIRIL for my stacking of the images, I did further adjustments as an exported TIF file with RawTherapee and GIMP. What I will point out is that the ISO noise does average out with this technique, the more the photos the higher the ISO you can use. And the effective resolution goes off the scale as each image is slightly shifted around in the pixel pattern of your sensor. Really 60 to 120 images are good for making a moon photo. The software does the work of aligning so the moon shifting around in the frame is not a problem.

Valentine Moon_infrared.jpg


And if I had taken 60 photos, I am sure it would have been even better. It was February and I think I had battery issues in the cold.
 
BF Hammer

BF Hammer

Senior Member
I also want to say you have a good focus here. There is detail in the craters. You could use some help in the post-processing. I took the liberty of working over your JPG, and if I was working directly with a Raw image it could be even sharper.

IMG_7375 edit.jpeg
 
BF Hammer

BF Hammer

Senior Member
I added local contrast, increased overall contrast, raised black level, added sharpness, lightly reduced noise, and increased exposure a little after all that. The noise reduction really wanted to erase detail so it was just enough to blend a bit.
 
Dawg Pics

Dawg Pics

Senior Member
I have gotten fuzzy moon images like that because the atmosphere wasn't clear or it was too turbulent to get a decent focus. If I see the edges going in and out of focus, then I don't bother.
Also, it could just be your lens as mentioned above. It might not perform well when zoomed to 300mm. Any chance you can rent a lens for a weekend and see if your images improve?
I don't know if you have tested your lens at infinity during the day.

This is one of mine that wasn't awesome. I added color to it in post. I am pretty sure I shot that on a bad night.
IMG_0452.jpeg
 
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R

Rink

New member
That’s a pretty good image.
We may indeed have atmospheric issues. This area has grown to metro proportions in recent years. Lots of light pollution S well as other kinds.
 
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