Calibrating a lens

Merlin5

Merlin5

Merlin5

Soldato
Joined
17 Aug 2009
Posts
18,378
Location
Finchley, London
I'm really not sure if my Tamron 70 to 300 is focusing right or if it's just me not knowing how to get sharp photos. But it can't be that hard to get sharp photos, I've practised enough, there's no way it should be this difficult.

But I struggle to get anything better than soft or blurry focus. At 300mm zoom, I'm taking photos of things that look ok on the LCD screen until I press the magnify button to 10x and it's always a bit blurry, even on a tripod. I've tried dozens of shutter speed, aperture and ISO setting combinations. For example, as a test, my camera is set up on a tripod in my kitchen looking through a very clean window at my bird feeder. The distance from lens to bird feeder is 23 feet. When I take a photo of a bird at that distance, I'm guessing it should be sharp at max magnification? It never is. And I don't think 23 feet is too far for a 300mm zoom is it?

I've looked into calibrating and have an idea how to do it. I know for instance to set the aperture to the widest, I know how to get to the AF micro adjustment function on my camera and adjust in increments for forward and back focus. And I found a youtube video where the guy has made a downloadable test paper with lines and numbers.

But I'm not sure what distance I have to be from an A4 sheet of test paper for 70 to 300mm. For calibrating it at 300mm, I think I need to focus on the paper a minimum of 25 feet away, does that sound about right?
 
And said:
Open your window.

Assuming this is for (mainly) small birds move your feeders closer or buy a pop-up hide and sit closer and be prepared to stop down to f8-f11 for depth of field. For any bigger birds you're using a zoom so adjust the focal length accordingly.
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Funny you should reply because I was looking at your amazing flickr images earlier and the level of detail and pixel clarity you get is what I'm looking for and not getting even remotely near. I can double zoom in on your photos and they don't get blurry! You've got way better gear and longer focal reach, but I think I should be able to achieve a lot better than I am with my gear.
So shooting through a window doesn't work I guess? I've got one large fixed window and one smaller openable one which doesn't open wide enough to properly take photos through. Yes, I think I'll move the feeder closer.
I got some nice squirrel shots at the same distance as the bird feeders but once I start to zoom in they lose sharpness. But the birds came out terrible without zooming.

Is there a good pop up hide you recommend?
 
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footman, that's great the way you've set up your perching branches. How far in feet away from the birds would you say you were for those images and what focal length?

I'm considering buying a crop sensor camera, the Canon 7D in fact since it can be bought very cheaply, and it would extend my 300m lens to 480m which I'm hoping would make a big difference.
Should I then be able to get something similar to the level of detail in your photos?
 
You might be right, olv. I took these two photos just before I read your reply about trying at less than max zoom. So I took these at 300mm, just over 20 feet away, through the opening of my window so no glass in the way. The squirrel didn't move during the shots.

ISO 800, f6.3, 1/320th, 300mm, vibration control on. I've not cropped or processed or sharpened as I want you to see exactly as it looks from raw. Now, do you or footman or anyone else think that this is good enough, as sharp as you would expect straight from the camera, or not?




I'm comparing to one of And's photos, I do hope he doesn't mind me linking to his website. This is what I'm trying to achieve:
https://www.andy-davis-photography.com/Galleries/Mammals/i-sGQrxNQ/A

On his squirrel photo, you can zoom right in and it has great detail and sharpness. Zooming on mine though loses sharpness and there certainly isn't the detail definition. So is there something I need to do better, or is it more a case of needing to own a better lens, and maybe camera?
 
footman said:
To achieve that level of sharpness requires a considerable investment in equipment, that particular image of Andy's was probably made using gear that costs in excess of £5000. It also involves a great deal of experience in fieldcraft and wildlife photography. However, we have all been in your situation when starting out doing wildlife photography and have gradually increased our abilities and level of gear. The lens suggested by @olv would certainly give you better results than the one you are using and the Canon 7D that you suggested earlier has given excellent results to many wildlife photographers over the years. I used that combination of Canon 7D and Canon 400mm f5.6L for years quite happily.
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I thought so, I definitely don't have anything remotely close to £5000 of gear. Just a 5D mk2 and Tamron lens. Was olv referring to a canon 400mm lens and not a tamron? I just looked up used canon 400mm 5.6 on MPB and it's over £700. :( I'm pretty sold on buying the 7D but I'll keep my 5D mk2. So, with the Tamron at 480mm on a 7D, it's not going to be much better than I have now in detail and sharpness? The canon 400mm on a 7D would give me a reach of 640mm which would be very nice. Is there a cheaper 400mm lens option almost as good? Sigma?

In terms of experience, no I don't have any. But I'm wondering what you or And would have done differently pointing my camera at that squirrel from the same place to get a better image?
 
Thanks olv and footman. At least you've put my mind at rest that it's less of me and more the limitations of my gear.
However, I do want a better lens, 400mm + and the 7D. Just can't justify spending over £700 for a canon lens.
I don't suppose it's going to be possible to buy a lens for around £200 that will give me close to what the canon 400mm would?
 
I took these this morning. A stray cat wandering into my garden. I think I oversharpened the middle photo as the eyes look a bit odd when really zoomed in. Overall, not bad I guess?

Cat-3.jpg

Cat-1.jpg

Cat-2.jpg
 
alchal said:
Yup that's the one I have.
It's heavy,but I can cope with it,kind of like exercise and photography roled into one so can't comment on the tripod need but I have found that it's better to be flexible with wildlife and tripods don't offer that.

If you look at flikr, search sonsofalchal (user name)
All my plane and animal shots are with that lense to give you an idea.
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I will have a look in a bit! :) Well I have to say, I'm a bit more impressed with my Tamron lens today than I was. Clearly, I needed to bring subjects closer as suggested earlier, so I moved the bird feeder to within 10 feet of my window. And clearly I needed as much sunlight as I can get. I finally managed to get a decent bird shot and only used 200mm. I've always had a long 1 x 1 piece of wood running across the bird table, so it fortunately acted as a perch above the feeders.
Took this at 200mm, f5.6 1/250th ISO 640

Is this a sparrow?

Bird-2.jpg
 
alchal said:
That's a really great shot,nice and sharp.
You will find a lot of lenses are not as sharp at the far end of the zoom especially if light is so so.

All about compromises really unless you are minted or a professional.

I would say so however despite my love for photographing birds I still struggle with recognition!
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Thanks alchal!

Can you give me a tip please. There was some noise on the background. So I used the luminance slider which pretty much removed that, but in the process it slightly softened the bird. I couldn't get the radial filter bubble to only isolate the bird, so what would be the best way for background noise reduction without affecting the main subject?
 
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