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  #1  
Old 01/10/2008, 03:27 PM
breutus breutus is offline
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has anyone used the...

tamron 70-300 macro lens for the canon? I just got one for christmas but it does not seem to be as good as I was expecting... is there something I am doing wrong, it just seems the 18-55 that came with the canon rebel xti is better than it!

Lucas
  #2  
Old 01/10/2008, 03:47 PM
Blazer88 Blazer88 is offline
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Posting some samples and knowing what you were expecting would help. FYI, the 70-300 isn't a true macro lens meaning it isn't capable of 1:1 magnification. I don't know if that is what you were expecting.
  #3  
Old 01/10/2008, 06:04 PM
breutus breutus is offline
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i'll post some pics when I get home tonight and sow you what I mean, and I did expect more out of the magnifacation of the image but thats exceptable, the problem is with how soft the whole image is nothing seems crisp. I'll post some in just a bit
  #4  
Old 01/10/2008, 06:32 PM
breutus breutus is offline
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these were shot at f/5.6

1/100

800 iso due to the extremely bright light

I am a major novice so this might have something to due with the issue.

Also a thought has occurred to me since I posted this, I have a bow front tank, the smaller lens may just not pick up on it as much?
  #5  
Old 01/10/2008, 09:55 PM
Phyl Phyl is offline
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Could you please take a picture of something outside of your aquarium? There are many aspects of aquarium photog that could be skewing your results. Please make sure that the item is "far enough" away, based on your lens specs.
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  #6  
Old 01/10/2008, 11:36 PM
maroun.c maroun.c is offline
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You should be using a tripod on these unless youare shooting faster than 1/300
Also when you say 800 iso dues to the extreemly bright light it seems you got the concept of ISO backwards, if you have very bright light it allows you to bring down your iso resulting in a less noisy image (still you have no noise in your pics) and then compensate by either using a faster shutter to freeze the action or maybe a smaller aperture (bigger number) to get more deapth of field. yo uare using 100 which very slow when using 300mm focal length. also you are using 5.6 aperture which is the widest aperture at full zoom and all lenses are knows to be a bit sharper when stepped down try to find where the sweepspot of this lens is, most probably around F8.
Your focus is not staright on and that may also be distortions due to the glass which are more prominent here it being a bowfront. With regular tanks you need to shoot perpendicular to the front glass which would be the shortest way through glass and thus the least distortions, in a bowfront yo ushould have your camera perpendicular to the glass in front of it. You are also whotting with a downward angle so this increases your distortions through thte glass try shotting straight into the glass. Phyls advice to try the lens outside the tank is also good this way you make sure that the lens is OK I would just add to use a tripod when using it as this way you eliminate motion blurr.
your exposures
  #7  
Old 01/11/2008, 12:54 AM
breutus breutus is offline
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thank you very much maroun.c a lot of useful insight there!

For starters I am using a tripod, but I can not remember if these were with the timer delay on or if it was push button. I don't understand usually where the f/ needs to be in relation to my shutter speed so I have been using shutter Priority and for some reason it always want to give me 5.6. Tomorrow when the lights kick on I will take the ISO down set the f/ a step or two higher and up my shutter speed and well see if that makes a difference. Wow I had it all backwards . I did notice though that the biggest difference seemed to be made when I shot at the perfect angle into the glass(though they were hard to find)

Thank you again I will post midday tomorrow with my results

Lucas
  #8  
Old 01/11/2008, 02:12 AM
maroun.c maroun.c is offline
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if you are not on manual and the camera is selecting this aperture then you don't have enough light to go to a smaller aperture (smaller aperture is a bigger number one like 8-11) so if you bring down the iso your camera will select a slower speed as it cannot go with a wider aperture than 5.6. your lens I guess can open till 3.2 or 3.6 when at the widest setting and this will decrease as you zoom to reach 5.6 at 300mm.
Try to see what values you get when all your lights are on and if the value is still 5.6 then yo ushould increase the ISO to more than 800 which will start to give some noise in the pics. you could either try a slower shutter speed if you're suing a tripod. for corals you could be fine using as slow as1/30 or even slower if they're not moving with the current. maybe shut your pumps to decrease their movement. one other alternative is ot use flash an external one would work better than the built in as you can angle it up and to the side to avoid reflections. flash would work better for fish shots where you need to shoot at least at 1/60 1/90 to freeze their motion. for orlas flash unfortunately washes out the colours of some corals so it's not always a good idea to use flash.
  #9  
Old 01/11/2008, 10:57 AM
breutus breutus is offline
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seems odd there couldn't be enough light! it's 2x250 14k MH and 4xT5 Actinic but maybe thats why I got confused with the direction your supposed to be going with ISO since I assumed it was more than enough light. I will play around with it more today in an hour when the Halides kick on. I'll post some pictures of the results..

Do you, or anyone, have a suggestion on a better lens in the same price range (about 200 dollars)?

Lucas
  #10  
Old 01/11/2008, 03:12 PM
maroun.c maroun.c is offline
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Then you would have a collection of 3 medium/bad quality lenses. Try to rule out if it's really a lens quality issue and then work on a choice plan on which lenses you need.
If your interest is in decent closeups or macro pictures then a macro lens might be just what you need and they cost more than this.
Sigma and Tamron also make lenses for canon and some of them are of good quality and lower price so maybe look at what lenses they offer and make sure to check with someone who is familiar with canon lenses on your choices before buying.
  #11  
Old 01/11/2008, 04:15 PM
breutus breutus is offline
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Thank you very much for the advice Maroun.c, Here is a few I have come up with and I am much happier at the moment.

These were all taken at 800 ISO 300mm and I took them from the side of the tank where it was flat so the bow front didn't interfere.

F/8 1/50


F/10 1/40


F/13 1/30


F/13 1/40


I had a Whole lot more but these were my favorites out of this set just slight changes really.

Thanks again for everyones help, and as always anymore advice would be appreciated.

Lucas
  #12  
Old 01/11/2008, 06:10 PM
oct2274 oct2274 is offline
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i can't see the pics so i can't comment on that. but i did see that you said you have extremely bright lighting in your tank. Why are you using such a high iso? higher iso's are usually used for lower light situations. typically you can get away with 100 iso = much better quality and better suited for high light situations and at the most I wouldn't be using more then iso 400. I wish i could see the pics, but they are blocked here at work. Will the lens not pull in enough light at lower iso's? See if you can take some pics at 200 iso at the same shutters speeds you tried above. I'm just curious to the outcome. If you can use a lower iso you will have less noise and typically a better pic. a tripod is a must for sure.
  #13  
Old 01/11/2008, 06:38 PM
breutus breutus is offline
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well for starts I don't see much noise especially for being 800 but when I take it down the picks were really dark unless i had the F/ at 15 or under or the shutter speed well below /30
  #14  
Old 01/11/2008, 07:35 PM
oct2274 oct2274 is offline
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got ya, sometimes you have to use higher iso's depending on the lens and the lighting, i was just curious if you had tried a lower ISO.
 

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