macro newbie needs advice please

[iwols]

hi all just a bit of advice please ,just started macro after seeing some superb pics on here,i am using a d90 with 18-70mm nikon lens and extension tubes,can anyone answer me the following please

1 with this setup i have to get very close to the subject to get focus 30mm ish
2 even when i do get focus i have to enlarge the subject quite a bit as it is only small on my final image ,any advice please,would the tamron 90mm lens make any difference and do the superb pics in the macro section get blown up anywat thanks guys

 

[modchild]

Most general purpose lenses wont get anything like a 1:1 ratio that purpose built macro lenses can. With tubes on you have to get closer to the subject which will help, but the main factor is the lens magnification. I shoot with a Canon setup, normally a 5D3 and a 100mm L macro lens and occasionally a tube set as well and once the photos are cropped the subject size is great.

 

[iwols]

Most general purpose lenses wont get anything like a 1:1 ratio that purpose built macro lenses can. With tubes on you have to get closer to the subject which will help, but the main factor is the lens magnification. I shoot with a Canon setup, normally a 5D3 and a 100mm L macro lens and occasionally a tube set as well and once the photos are cropped the subject size is great.

Thanks for that can you post a pic of something small that has not been touched or cropped just for a comparison thanks again

 

[mrodgers]

As well as extension tubes there are quite a few other ways of getting more magnification without a proper macro lens, some are explained here: http://photography-on-the.net/forum/showthread.php?t=807056 . I use a 50mm lens reversed on the front of the kit lens (bit more detail about this on the link), which gives photos like the one below (which is only slightly cropped, probably about 70% of the original photo left):

IMG_5231 by m.rodgers1, on Flickr

 

[Moos3h]

Do a search for the Raynox macro - a cheap way of getting into it.

The difficult thing with Macro is getting enough of the subject in focus, due to DoF issues. It's worth persevering though

 

[iwols]

thanks for that guys ive loaded a test shot here for you to look at although not great focus but my main problem is the actual size of the fly compared to the overall size of the photo..the lens i used was 18-70mm with an extension tube,the camera was nearly touching the fly,any suggestions appreciated

test by iwols, on Flickr

 

[Dogfish_magnet]

to work out the magnification take a photo of a ruler at the maximum magnification then divide size of your camera's sensor 22.3mm for a canon crop sensor by the number of mm's in the image. If you were using a true macro lens you would see 22.3 mm so you would get a ratio of 1:1 (life size), if you see 11mm in the image you would get a ratio of 2:1 , twice life size and if you see 44.6mm you will have a 0.5:1 ratio or half life size.

1-1 life size

0.5:1 - half life size

 

[iwols]

to work out the magnification take a photo of a ruler at the maximum magnification then divide size of your camera's sensor 22.3mm for a canon crop sensor by the number of mm's in the image. If you were using a true macro lens you would see 22.3 mm so you would get a ratio of 1:1 (life size), if you see 11mm in the image you would get a ratio of 2:1 , twice life size and if you see 44.6mm you will have a 0.5:1 ratio or half life size.

1-1 life size

0.5:1 - half life size

cheers heres my 3 pics with the 3 different tubes at 70mm,they range from the lens being about 1 inch away to basically touching which is basically unworkable any comments please

70mm with 10mm ext (1204 x 800) by iwols, on Flickr

70mm with 10mm ext (1204 x 800) by iwols, on Flickr

70mm with 68mm ext (1204 x 800) by iwols, on Flickr

 

[iwols]

just a point dogfish how far was your lens away from the tape at 1:1 please

 

[Dogfish_magnet]

just a point dogfish how far was your lens away from the tape at 1:1 please

These were shot with a macro lens, and maximum magnification is always at the closest focussing distance of the lens, which varies with focal length. MWD is the distance from the end of the lens to subject in the chart below.

 

[iwols]

thanks dogfish so what your saying is you were 6inch away for your 1:1 with the canon 100mm,and that you would be 4.8 inch away with the tamron 90mm and 7.6 inch away with the sigma 150mm,so why would you not be better with the canon 180mm as you could be 9inch away for 1:1 cheers

 

[Dogfish_magnet]

thanks dogfish so what your saying is you were 6inch away for your 1:1 with the canon 100mm,and that you would be 4.8 inch away with the tamron 90mm and 7.6 inch away with the sigma 150mm,so why would you not be better with the canon 180mm as you could be 9inch away for 1:1 cheers

Longer working distance comes at a cost the Canon 180mm weighs 1090g which is difficult to hand hold, and costs around £1170 whhere as the Canon 100m weighs 600g and costs £365

 

[Alastair]

thanks for that guys ive loaded a test shot here for you to look at although not great focus but my main problem is the actual size of the fly compared to the overall size of the photo..the lens i used was 18-70mm with an extension tube,the camera was nearly touching the fly,any suggestions appreciated

Did you have the lens set at 18mm or 70mm?

Using extension tubes the magnification is greatest when the lens is at its widest (ie. 18mm not 70mm).

 

[iwols]

Did you have the lens set at 18mm or 70mm?

Using extension tubes the magnification is greatest when the lens is at its widest (ie. 18mm not 70mm).

thanks when i tried at 18mm it would not focus it was very close to the object at 70mm