For these I look at the 9 in the date. On yours the 9 doesn't appear to be curled in enough to be a small date. They are both large dates imo.
Your welcome. Here is a link with a lot of great info on these. http://lincolncentresource.com/smalldates/1970Ssmalldate.html
Both are large date for me the tail of the 9 is the key ... Look at the link provided by @MontCollector to help you better understand .. Small vs Large Dates 1970 s is not an easy attribute for most novice collectors so don't feel bad .. experience on this one is needed.
The reference photo by @spirityoda shows a great of display of differences of the two type nines (9) .. Notice on the Large Date the tail of the 9 is squared off (location pointed to by the arrow) while on the 9 of the Small Date the tail looks Pinched off... It helps to use 10-16X loupe. Where the 9s tail points (to center or bottom of 7) can be a bit confusing as it helps to have the coin properly positioned for me with the Lincoln head pointing straight up and using high magnification... One of the few times I would recommend a 16x Loupe.