Nikon 70-300mm Lens Blur question

Lonnie1212 · May 12, 2020

Hi Folks,

Today I accidentally took a small bird picture at 170mm. Normally I shoot all my bird pictures at 300 mm. When I zoomed in on the 170mm picture. It was noticeably clearer than the 300mm pictures. Could my lens be getting a blur at 300 mm? I am using a Nikon D610 with this lens.

Thank you,

Lonnie

weepete · May 12, 2020

What was your shutter speed?

the rule of thumb is to use a shutter speed of 1/focal length to avoid camera shake so at 300mm you should be at 1/300th sec or faster. It gets a bit more complicated as you also need a shutter speed fast enough to freeze motion. Just exactly how fast you need depends on the bird and what they are doing. For perched birds 1/300th sec should be ok, for large birds in steady flight 1/800th is normally fast enough, if they are activley changing direction then 1/1000th sec or more. I was shooting sparrows and starlings yesterday and had to bump the shutter speed right up to 1/4000th sec in an attempt to capture the action.

Lonnie1212 · May 12, 2020

weepete said:
What was your shutter speed?

the rule of thumb is to use a shutter speed of 1/focal length to avoid camera shake so at 300mm you should be at 1/300th sec or fasterI . It gets a bit more complicated as you also need a shutter speed fast enough to freeze motion. Just exactly how fast you need depends on the bird and what they are doing. For perched birds 1/300th sec should be ok, for large birds in steady flight 1/800th is normally fast enough, if they are activley changing direction then 1/1000th sec or more. I was shooting sparrows and starlings yesterday and had to bump the shutter speed right up to 1/4000th sec in an attempt to capture the action.

The shutter speed was 1/500 in both pictures. In both pictures I am looking at the grain in the birdfeeders as well. I have heard people say that certain lenses can have a blur when fully extended. I suspect that this is the case. Today or tomorrow I will go out and conduct an experiment with different focal lengths.

I admire you for being able to capture birds in flight. I have only been birding for about one week. There is so much to learn. I appreciate your advice. Will also try the 1/800 and 1/4000 shutter speeds out of curiosity.

Derrel · May 12, 2020

The lens might perform at a sub-par level at 300mm. Many tele-zoom lenses do _not_ perform at their best when zoomed to their longest ranges.. the 70-300 G I had back in the early 2000's was good up until about 220...above that it was sub-par. It had a lot of color fringing at its longer settings.

JBPhotog · May 12, 2020

Try placing your camera on a tripod and shooting a subject at 300mm, this will indicate whether the platform(you) were/are stable enough to shoot at 1/500 and full zoom. Try some higher shutter speeds to see if IQ improves,

Lonnie1212 · May 12, 2020

JBPhotog said:
Try placing your camera on a tripod and shooting a subject at 300mm, this will indicate whether the platform(you) were/are stable enough to shoot at 1/500 and full zoom. Try some higher shutter speeds to see if IQ improves,

Okay, I will give it a try.

Lonnie1212 · May 12, 2020

Derrel said:
The lens might perform at a sub-par level at 300mm. Many tele-zoom lenses do _not_ perform at their best when zoomed to their longest ranges.. the 70-300 G I had back in the early 2000's was good up until about 220...above that it was sub-par. It had a lot of color fringing at its longer settings.

Thank you for telling me this. I was thinking this might be the case. I will conduct some experiments.

Derrel · May 12, 2020

I noticed the problem back in the 6MP days of the D70...some relatively inexpensive zooms fare poorly on 24MP sensors.

Tests are helpful to determine the nuances of lenses.

weepete · May 13, 2020

Lonnie1212 said:
The shutter speed was 1/500 in both pictures. In both pictures I am looking at the grain in the birdfeeders as well. I have heard people say that certain lenses can have a blur when fully extended. I suspect that this is the case. Today or tomorrow I will go out and conduct an experiment with different focal lengths.

I admire you for being able to capture birds in flight. I have only been birding for about one week. There is so much to learn. I appreciate your advice. Will also try the 1/800 and 1/4000 shutter speeds out of curiosity.

I'm still practising with birds in flight myself, got a way to go before I'd consider myself competent. I've not had the chance to get out much and practise since last September so I'm a bit rusty. Getting small birds with some movement is proving particularly tricky.

But yeah, if you are seeing it in other areas it does point to the lens. I had an old Canon 70-300mm f3.5-5.6 that was pretty soft and a lot of CA, close up with lagre subjects it was ok but I soon found myself wanting sharper and ultimatley the image quality of the lens just didn't cut it. Even my 150-600mm is better at 400mm than 600mm so it does happen.

I'd try it at a few shutter speeds and check if the lens is back/front focusing then try some shots with similar framing at different focal lengths. I normally try to be reasonably sure that I've eliminated user error before looking at the lens, though it's always a possibility that it's just not acceptably sharp.

Lonnie1212 · May 13, 2020

weepete said:
Lonnie1212 said:

The shutter speed was 1/500 in both pictures. In both pictures I am looking at the grain in the birdfeeders as well. I have heard people say that certain lenses can have a blur when fully extended. I suspect that this is the case. Today or tomorrow I will go out and conduct an experiment with different focal lengths.

I admire you for being able to capture birds in flight. I have only been birding for about one week. There is so much to learn. I appreciate your advice. Will also try the 1/800 and 1/4000 shutter speeds out of curiosity.

Click to expand...

I'm still practising with birds in flight myself, got a way to go before I'd consider myself competent. I've not had the chance to get out much and practise since last September so I'm a bit rusty. Getting small birds with some movement is proving particularly tricky.

But yeah, if you are seeing it in other areas it does point to the lens. I had an old Canon 70-300mm f3.5-5.6 that was pretty soft and a lot of CA, close up with lagre subjects it was ok but I soon found myself wanting sharper and ultimatley the image quality of the lens just didn't cut it. Even my 150-600mm is better at 400mm than 600mm so it does happen.

I'd try it at a few shutter speeds and check if the lens is back/front focusing then try some shots with similar framing at different focal lengths. I normally try to be reasonably sure that I've eliminated user error before looking at the lens, though it's always a possibility that it's just not acceptably sharp.

Sounds like good advice. I will try and get out soon. We are expecting rain in Illinois and the temperatures have dropped considerably.

pocketcamera · Jul 21, 2020

I have the af-p 70-300. its good lens. its just that when I looked at the images in the free copy of irfaviewer, there IS a noticeable change in quality once I get past the bird I was focused on.

someone tried to explain that the lens may/is/was focusing IN FRONT of the object I wanted to and the depth of field was causing the issue. I couldn't understand the explanation, by a person who wanted me to buy a used lens from him, so I just ignored it. But when you take the medium size option for photo size, things can look odd

JBPhotog · Jul 21, 2020

Front or rear focussing lenses can be an issue. To keep it in simple terms, this essentially means the indicated focus plane in the viewfinder is not where the lens is actually focussing. Some cameras have the ability to adjust the focus plane indicator to match what is actually in focus and store those setting per the lens attached.

Depth of field is a different issue. All lenses will exhibit the depth of field into thirds, one third in front of the focus plane and two thirds behind the focus plane. Of course the amount of DoF is determined by the f-stop chosen.

An additional parameter of sharp images is diffraction which is impacted by the chosen f-stop. In other words stopping a lens down to f16 or f22 will achieve greater DoF but at the expense of overall sharpness due to diffraction.

stk · Jul 30, 2020

Is it the AF-S version? This lens needs to be stopped down when you pass 200 mm to perform it's best. I still shoot mine wide open at 300 mm and it's perfectly fine, just not great.

Lonnie1212 · Aug 5, 2020

stk said:
Is it the AF-S version? This lens needs to be stopped down when you pass 200 mm to perform it's best. I still shoot mine wide open at 300 mm and it's perfectly fine, just not great.

Thank you for the advice STK. I will try stopping it down the next time I use it.