Sigma 150-500 - not enough???

WideEyedFox

WideEyedFox

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I recently purchased a Sigma 150-500mm f5-6.3 APO DG OS HSM to use with my Nikon D90 for both motorsport (MotoGP recently) and in Kenya next week.
I am worried that their is either a problem with the lens, or I am not using it correctly, or that I am expecting too much from it.

Stood at Club corner at Silverstone recently, with me 10-12 feet from the fence with a bunch of photographers (must be a photographer hot spot!) I shot the photo below at nearly maximum zoom.

DSC_3174.JPG [4288x2848] [4.5Mb]

Anyone knowing the area will have an idea of distance, but it seems to be about 150 feet (50 yards to me!).

Does this seem right? There is a photo in a book I am reading (Travel Photography Footprint Travel Guide Steve Davey) of London, which shows zoom levels up to a 300 and they seem much MUCH better than what I am getting with this 500.

PEWONC ?? (Problem Exists With Operator Not Camera)

Help and advice appreciated.
 
You can get an idea of the focal length required for a shot using the equation.....

distance to subject (metres) / size of subject (metres) * sensor width (mm)

So, we'll say you were 50m from the subject, the subject is 2 metres long (at the angle of approach) and your sensor is 24mm wide (I believe?). This means that you'll fill the frame with a lens of 600mm focal length.
Looking at the shot, you were either further from the track than you guessed or your focal length was much shorter than the "nearly maximum zoom" that you think you used..
Or there's a problem with the kit.

Bob
 
Which Parks are you visiting in Kenya,

We were there last week,

I got rid of my Sigma 150-500 and replaced it with the Canon 100-400L,

In Tsavo East/West I found the 100-400 Lacked reach at times, with the Big Cats often managing only to get into about 1/4 sensor fill on an animal. Due to the restrictions on sticking to the main tracks.

In Amboseli the animal count is very low at this time of year, (Oct/Nov) best time there as animals move in during the dry season. And did not get much at all

The Mara the 100-400 was fine with the open driving making it much easier to position and get a good frame fill with 400mm and even less.

So a lot will depend on the parks you visit and luck of the draw on the day (Plus Ability of the driver!)

Good Luck and have a great trip.
 
Canon Bob said:
distance to subject (metres) / size of subject (metres) * sensor width (mm)
Click to expand...
Thanks Bob.

Looking at the math side of things - that makes sense. I think it could be me expecting too much of it.
I have looked through some other shots, and am pretty sure they were at maximum zoom, so the one above could not have been.

If you add a few more metres distance and take off the amount of zoom I thought I was using - it seems right according to that formula - thanks. :thumbs:


501cards - Not sure of the parks yet - it's our family holiday to Mombasa, and we have a contact in Namibia as well if we can afford the internal flight. Timing wise we have to fit it in with school holidays, so will try and make the best of it.
 
If you look at your EXIF data, that should tell you what zoom length you were using.
 
andrewc said:
If you use Google Earth you can use the ruler tool to try and work distance from where you are to where the bike was.
Click to expand...
Good idea! :thumbs:

...
...
...

It's an old image on Google Earth - but the distance is around the 55m + mark.

55 / 2 * 24 = 660

Nikon have the sensor size down as "23.6" - in camera terms do you round up to 24, or should I use 23.6 in my calculations?
 
WideEyedFox said:
Good idea! :thumbs:

...
...
...

It's an old image on Google Earth - but the distance is around the 55m + mark.

55 / 2 * 24 = 660

Nikon have the sensor size down as "23.6" - in camera terms do you round up to 24, or should I use 23.6 in my calculations?
Click to expand...

Close - your actually 59.57m away from your point of focus the data is in the EXIF
 
WideEyedFox said:
Nikon have the sensor size down as "23.6" - in camera terms do you round up to 24, or should I use 23.6 in my calculations?
Click to expand...

The difference in resultant focal length is only 11mm so I'd use the rounded up value for easier mental arithmatic.

Bob
 
I feel intimidated by the fact you guys know more about my photo and my location in relation to the subject than I do - and you weren't even there! :lol:

Thanks for the help and advice everyone - I really appreciate it.

Another lesson learned :thumbs:
 
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