Aperture advice on my 300mm lens please

silure130

silure130

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Rick
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hi
I'm just getting into bird photography and spend my time walking around the local marsh. I have a D7000 & Nikon 300mm AF/S F4 lens. My Nikon 1.4 teleconverter arrives this week so I'll have a bit more reach.
I got talking to this chap in one of the hides and said that I'd only just started and its a steep learning curve for me.

He gave me a bit of good advice on different settings and he also said that it would be better for me to just keep the aperture on F5.6 all the time. Is this good advice for birding because choosing which apeture is one thing I'm struggling with.

thanks
 
Well if you use the converter you will lose a stop so your max aperture will be f5.6.

I'm not sure that this is good advice. The aperture that photographers use is sometimes dictated by the light available which forces you to shoot wide open to obtain a decent shutter speed. At other times the photographer may be trying to isolate a bird from its background and will deliberately shoot wide open even though the light available would allow them to stop down and stil get a fast shutter speed.

Depth of field is quite shallow at f5.6 and there will be times if the light allows that you will want to stop down to get more of the bird in focus.

As an example you may focus on a birds eye that is head on to you at f5.6 @ 1/2000. It is possible that the tip of the bill closest to you will be out of focus. By stopping down and shooting at f8 @ 1/1000 the bill will come into focus.

Shooting all the time at f5.6 limits your scope significantly IMHO.

Giving advice regarding aperture is difficult. You should experiment for yourself and see how using different apertures can change the appearance of your images.

Regards
 
Gaz J said:
Well if you use the converter you will lose a stop so your max aperture will be f5.6.

I'm not sure that this is good advice. The aperture that photographers use is sometimes dictated by the light available which forces you to shoot wide open to obtain a decent shutter speed. At other times the photographer may be trying to isolate a bird from its background and will deliberately shoot wide open even though the light available would allow them to stop down and stil get a fast shutter speed.

Depth of field is quite shallow at f5.6 and there will be times if the light allows that you will want to stop down to get more of the bird in focus.

As an example you may focus on a birds eye that is head on to you at f5.6 @ 1/2000. It is possible that the tip of the bill closest to you will be out of focus. By stopping down and shooting at f8 @ 1/1000 the bill will come into focus.

Shooting all the time at f5.6 limits your scope significantly IMHO.

Giving advice regarding aperture is difficult. You should experiment for yourself and see how using different apertures can change the appearance of your images.

Regards
Click to expand...

Superb info for a newbie like me. Many thanks :)
 
Also remember the distance to the subject will 'dictate' the depth of field the focal length will give for any particular aperture. An aid to understand how large the DoF will be this calculator http://www.dofmaster.com/dofjs.html

HTH :)
 
I've got the same setup as you, it's great and works really well. The point about distance to subject affecting DoF gas to be taken into account. I photography deer mainly but have started photographing birds. As you have to usually get closer to birds as they are a smaller subject DoF is critically for the bird to all be in focus. There are DoF apps for phones and I'm always checking the DOF calculation on the app.
 
When calculating the focal length do you allow for the crop factor and the TC 1.4. My D7000 & 300mm lens x 1.5 x 1.4 = 630mm.

I can roughly gauge the distance to the subject, say a bird 20ft away.
What would you put in the calculator to get the best result youd be happy with.
thanks
 
silure130 said:
When calculating the focal length do you allow for the crop factor and the TC 1.4. My D7000 & 300mm lens x 1.5 x 1.4 = 630mm.

I can roughly gauge the distance to the subject, say a bird 20ft away.
What would you put in the calculator to get the best result youd be happy with.
thanks
Click to expand...

AFAIK the drop down selector lets you pick the body and hence the crop factor is accounted for so you need to know the TC multiplied FC only I think.

HTH ???
 
S30, its reasonable to expect you and the camera to be roughly at least 40 or 50ft from a bird, unless you're in a hide of some such

As posted from Box B regarding the DOF, @ 420mm ( 300mm + 1.4 TC ) your in-focus area is less than 1ft at 50 ft, and just over 6" at 40ft. Ok for tiny and slightly bigger birds

So as posted, it may be better to stop down from your Max of f5.6 to f8 if the light permits. If not, up the ISO a stop and see if you can retain enough SS. The in-focus area at 50ft then becomes 1.3ft at f8, which should be ok for getting a whole bird in focus depending. Swans wont be any good

At larger distances from your subject than 50ft, your aperture of f5.6 will be fine unless your IQ is not so good at max aperture, or you encounter a giant Roc bird
 
The camera selection drop down box takes into account the crop factor of the sensor. Without the 1.4TC the focal length you select would be 300mm, with the 1.4TC the focal length you select would be 450mm.

Have a look at how changing the camera will affect the DoF, a cropped sensor will give a smaller DoF than a full frame sensor due the longer effective focal length with the cropped sensor.

With the 1.4TC at 20ft you have a very small DoF, using a smaller aperture (higher F number) will give you more DoF but would reduce the amount of light hitting the sensor so you have to compensate by using either a higher ISO or a slower shutter speed.

Keeping a fast shutter speed helps to reduce subject movement blur and camera shake blur, don't forget to keep the shutter speed 1/focal length to ensure no camera shake blur when hand held. the D7000 is quite good for higher ISO so don't worry too much about raising the ISO.

Try out the auto ISO function on the D7000,it's pretty good. You can set the minimum shutter speed and the maximum ISO level. I use it all the time for wildlife, i usually use either aperture priority or manual. I keep an eye on the ISO and try to compensate where necessary but I would rather get the shot with a higher ISO than get an under-exposed or blurred shot.
 
I would test the lens and TC out with all the apertures and see which one is the sharpest. You might be surprised when you test them how much difference there is in quality from the highest aperture to the lowest.

Most older lenses (I'm not sure about modern lenses) produced the best results at f8. So I would work around that and then up the ISO to get the desired shutterspeed. As others have said the D7000 is pretty good at high ISO's so test those out as well to see where you start to loose quality. You can really ramp up the ISO these days to silly numbers and still retain the quality, but you do have to test it first on a static 'controlled' object and then zoom into the pictures afterwards.
 
The 300 f4 AF-S is sharp wide open, even with the 1.4 or 1.7TC fitted, so no worries if you have to open it up because of the light, however aim to use it at f7.1 to give you a little more depth of field.
 
photogav said:
I would test the lens and TC out with all the apertures and see which one is the sharpest. You might be surprised when you test them how much difference there is in quality from the highest aperture to the lowest.
Click to expand...

And how little difference there is between f5.6, f13 and intermediate values.
 
photogav said:
I would test the lens and TC out with all the apertures and see which one is the sharpest. You might be surprised when you test them how much difference there is in quality from the highest aperture to the lowest.
Click to expand...

I'd second the advice to try lots of apertures and have a look at the difference - it certainly helped me when I was starting out - I picked a sunny day, found a hide with plenty of waterfowl and experimented with all the f stops with constant settings for everything else - and there will be shots where a shallow DOF can work quite well - you might want a close up shot of a bird head on and actually choose to have they eyes in sharp focus and the beak out of focus in the foreground?
 
Interesting information. I have just downloaded DOF calculator by AIMEN RG for android from the play store.

It gives you the relevant information and the little display at the bottom gives you the foucus limits and DOF.
 
The constraint in usually the available light. I tend to mainly do Bird photography from Autumn through to Spring, when the migrants arrive and leave and when there is less foliage around which may obscure your subject. However that usually means that at this time of year there is less light around and more bad weather (much like our British summers for the last five years). Its the usual trade off between ISO, Aperture and Shutter speed and how good your camera is at handling noise at high ISO settings. Small birds move quickly, so you want a high shutter speed, larger birds give you more time and you can drop it a stop. A flock of Birds in flight will definitely benefit from dropping down to f/8 or more unless your wanted to pick out a single bird. For most single birds on the ground, or in tree with no sky background, I will usually shoot wide open at f/4 on my 500mm or f/5.6 if using the 1.4x extender with it.
 
Just thought Id drop in on the subject of crop factors and depth of field. As far as I can see you dont get a shorter DOF because of the crop factor effect on the focal length.

As an example I fired up the DOF calculator, set it for 1.6 crop camera, 50mm lens aperture f4 and distance to subject of 10m.

This gives far limit 14.34m
Near limit 7.68m
DOF 6.66m

if we multiply the 50mm by 1.6 that gives 80mm on a full frame, I then set my DOF calculator to a 1.0 or full frame, set lens to 80mm left the rest the same, that gives

Far limit 12.19m
Near limit 8.48m
DOF 3.72m

So (I think) what I am saying is, multiplying your focal length by 1.6 and then using that focal length as the basis for working out your DOF is not correct.

But I may have confused myself. :thinking:
 
DorsetDude said:
Just thought Id drop in on the subject of crop factors and depth of field. As far as I can see you dont get a shorter DOF because of the crop factor effect on the focal length.

As an example I fired up the DOF calculator, set it for 1.6 crop camera, 50mm lens aperture f4 and distance to subject of 10m.

This gives far limit 14.34m
Near limit 7.68m
DOF 6.66m

if we multiply the 50mm by 1.6 that gives 80mm on a full frame, I then set my DOF calculator to a 1.0 or full frame, set lens to 80mm left the rest the same, that gives

Far limit 12.19m
Near limit 8.48m
DOF 3.72m

So (I think) what I am saying is, multiplying your focal length by 1.6 and then using that focal length as the basis for working out your DOF is not correct.

But I may have confused myself. :thinking:
Click to expand...

You are right. DoF is related to the lens' actual focal length irrespective of the crop factor. This means that with a 300mm on a 1.5 crop, the lens will still have a focal length of 300mm but an effective focal length of 450mm, but with the DoF of a 300mm lens.
 
I have a DOF calculator on my android smartphone, as i am fairly new to my 300mm lens I can checkout DOF settings on the move :)
 
Prime telephotos ought to be sharp wide open. If you're not comfortable with it's quality wide-open, then there is something wrong. I'm b*ggered if I'm going to pay all that money and lug all that weight around if I'm not going to take advantage of the light-gathering capabilities. So I shoot wide-open with my lenses 95% of the time, as shutter speed in this miserable country is always dire and I normally need to squeeze out every millisecond. Except when at minimum focus range, when the lenses require stopping down to get the bill AND eye (for instance in focus) - note that this rarely happens in the country, birds are much easier abroad. The exception is probably flight photography where the additional d-o-f is helpful for wingtips and my default setting would be manual exposure with f8-10 as the aperture.
Rgds
Jonathan
 
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